*161*386Senate Bill No. 1391, enacted by the Legislature in 2018 (2017-2018 Reg. Sess.) (Stats. 2018, ch. 1012, § 1, eff. Jan. 1, 2019) (Senate Bill No. 1391), eliminated prosecutors' ability to seek transfer of 14- and 15-year-olds from juvenile court to criminal (adult) court, except where such a minor is alleged to have committed a specified serious offense and is not apprehended prior to the end of juvenile court jurisdiction. ( Welf. & Inst. Code, § 707, subds. (a)(1), (2) & (b).)1
Recently, in People v. Superior Court (T.D.) (F078697, Aug. 5, 2019) 38 Cal.App.5th 360, ----, ----, 250 Cal.Rptr.3d 661, 2019 WL 3542874 [2019 --- Cal.App. LEXIS ----, *----, *----] (slip opn. at pp. 2, 19) (T.D. ), we held that Senate Bill No. 1391 validly amended Proposition 57, the Public Safety and Rehabilitation Act of 2016 (Proposition 57 or the Act). The Act had permitted such transfer, but only with juvenile court approval.2 For the reasons stated in T.D. , we reject the claim of petitioner, the District Attorney of Kings County (the District Attorney), that Senate Bill No. 1391 unconstitutionally amended Proposition 57. We also address issues not before us in T.D. We hold: (1) Senate Bill No. 1391 is not an unconstitutional amendment of Proposition 21, the Gang Violence and Juvenile Crime Prevention Act of 1998 (Proposition 21); (2) Senate Bill No. 1391 is not unconstitutionally vague; (3) Senate Bill No. 1391 applies retroactively; and (4) the murder charge against real party in interest I.R. (I.R.) allegedly committed when he was age 15 cannot be transferred to criminal court based on a separate felony offense he allegedly *387committed when he was age 17. Accordingly, we deny the petition for writ of prohibition and/or mandate.
PROCEDURAL HISTORY 3
On November 20, 2014, Roman Aguayo was stabbed to death. Six days later, in Kings County Superior Court case No. 14CM-4797A, the District Attorney directly charged I.R., in criminal court, with murder committed in association with or for the benefit of a criminal street gang *162( Pen. Code, §§ 186.22, subd. (b), 187, subd. (a)) and active participation in a criminal street gang ( id. , § 186.22, subd. (a) ).4 I.R., who was 15 years old on the date of the homicide, was held to answer on those charges on February 4, 2015, following a preliminary hearing.
On November 8, 2016, voters enacted Proposition 57. It went into effect the next day. (See Cal. Const., art. II, § 10, former subd. (a).) The Act eliminated prosecutors' ability to file charges against juveniles directly in criminal court. Certain categories of minors - 16- and 17-year-olds who violated any felony criminal statute, and 14- and 15-year-olds who committed enumerated serious offenses, including murder - could still be tried in criminal court, " 'but only after a juvenile court judge conduct[ed] a transfer hearing to consider various factors such as the minor's maturity, degree of criminal sophistication, prior delinquent history, and whether the minor [could] be rehabilitated. [Citation.]' [Citation.]" ( People v. Superior Court (Lara) (2018) 4 Cal.5th 299, 305-306, 228 Cal.Rptr.3d 394, 410 P.3d 22 ( Lara ); see § 707, former subds. (a), (b).) The Act further eliminated the presumption that a minor alleged to have committed certain specified serious offenses was not a fit and proper subject to be dealt with under the juvenile court law. (See § 707, former subd. (c).) As a result of Proposition 57's enactment, criminal proceedings in case No. 14CM-4797A were suspended, and the case was certified to juvenile court, pursuant to section 604.
On December 12, 2016, the District Attorney filed a juvenile wardship petition (§ 602) in case No. 16JQ-0087. Count 1 alleged a violation of Penal Code section 187, subdivision (a) for the murder of Roman Aguayo, plus a gang-murder special circumstance (id. , § 190.2, subd. (a)(22)) and a gang enhancement (id. , § 186.22, subd. (b)(1)(C)). Count 2 alleged a violation of Penal Code section 186.22, subdivision (a) (active participation in a criminal street gang), committed on the same date as the murder. Count 3 alleged a *388violation of Penal Code section 245, subdivision (a)(4) (assault by means of force likely to produce great bodily injury), together with a gang enhancement ( id. , § 186.22, subd. (b)(1)(A) ), arising out of an assault I.R. allegedly committed in juvenile hall on November 20, 2016, when he was 17 years old.
At the District Attorney's request, and following a hearing pursuant to section 707, former subdivision (a), I.R. was transferred to criminal court on all counts. Criminal proceedings were reinstated in case No. 14CM-4797A, and a criminal complaint was filed in case No. 17CM0680, charging the assault and gang enhancement that had been alleged as count 3 in case No. 16JQ-0087. On April 26, 2017, I.R. was held to answer in case No. 17CM0680.
On October 4, 2017, the jury deadlocked on the murder charge in case No. 14CM-4797A. On October 12, 2018, at or around the outset of retrial, I.R. moved to be returned to juvenile court, based on the criminal court's lack of jurisdiction due to the passage and signing by Governor Edmund G. Brown, Jr., of Senate Bill No. 1391. The motion was denied on October 16, 2018, because the new law was not yet in effect.
On October 22, 2018, jury trial in criminal court was reset to January 7, 2019, after insufficient prospective jurors were summoned to permit selection of a jury. On January 7, 2019, I.R. asked the court to rehear his motion to dismiss the case due to lack of jurisdiction. The court granted *163the rehearing request and dismissed the case.
That same day, the District Attorney filed a juvenile wardship petition (§ 602) in case No. 19JQ-0003, alleging I.R. committed murder with a gang-murder special circumstance and gang enhancement ( Pen. Code, §§ 186.22, subd. (b), 187, subd. (a), 190.2, subd. (a)(22) ; count I), and was an active participant in a criminal street gang ( id. , § 186.22, subd. (a) ; count II).5 The District Attorney requested that I.R. be transferred to criminal court pursuant to section 707, subdivision (a).6 I.R. opposed the transfer request on the ground Senate Bill No. 1391, which had since taken effect, bars a minor who was 15 years old at the time of the alleged offense from being tried in adult court. The District Attorney argued Senate Bill No. 1391 is unconstitutional and does not apply retroactively.
*389A hearing on the transfer request was held on February 14, 2019. The court ruled that because I.R. was 15 years old at the time of the alleged murder and was apprehended before the expiration of juvenile court jurisdiction, the court lacked jurisdiction to transfer him to criminal court. Accordingly, it denied the District Attorney's transfer motion and set the matter for a jurisdictional hearing.
The District Attorney petitioned this court for a writ of prohibition and/or mandate, making the same arguments he made below. We stayed the juvenile court proceedings and issued an order to show cause.
DISCUSSION
The District Attorney raises a number of challenges to Senate Bill No. 1391. The first is that it is unconstitutional "because it changes Proposition 57's provision that a juvenile judge must determine if a juvenile should be prosecuted in criminal court; [Senate Bill No.] 1391 is inconsistent with and does not further the voter[s'] intent in passing Proposition 57." (Some capitalization & boldface omitted.) As previously stated, we rejected this claim in T.D. , supra , 38 Cal.App.5th at pages ---- - ----, 250 Cal.Rptr.3d 661 [2019 Cal.App. LEXIS ----, *---- - *----] (slip opn. pp. 7-19), and we find no reason to revisit our analysis and conclusion in that case. Accordingly, we turn to the District Attorney's remaining contentions.7
I
Senate Bill No. 1391 is not an unconstitutional amendment of Proposition 21.
Proposition 21 was approved by voters at the March 7, 2000 Primary Election. "Proposition 21 revised the juvenile court law to broaden the circumstances in which minors 14 years of age and older [could] be prosecuted in the criminal division of the superior court, rather than in juvenile court." ( Manduley , supra , 27 Cal.4th at p. 549, 117 Cal.Rptr.2d 168, 41 P.3d 3.) In some instances - such as special circumstance murder where the minor *164allegedly personally killed the victim - it mandated such prosecution. (§§ 602, former subd. (b), 707, former subd. (d); see Lara , supra , 4 Cal.5th at p. 305, 228 Cal.Rptr.3d 394, 410 P.3d 22.)
An uncodified section of Proposition 21 provides: "The provisions of this measure shall not be amended by the Legislature except by a statute passed in *390each house by rollcall vote entered in the journal, two-thirds of the membership of each house concurring, or by a statute that becomes effective only when approved by the voters." (Ballot Pamp., Primary Elec. (Mar. 7, 2000) text of Prop. 21, § 39, p. 131.) Accordingly, the Legislature may amend Proposition 21's statutory provisions without voter approval only by a two-thirds vote of each house. (See Cal. Const., art. II, § 10, subd. (c); People v. Superior Court (Pearson) (2010) 48 Cal.4th 564, 568, 107 Cal.Rptr.3d 265, 227 P.3d 858 ; see also In re G.Y. (2015) 234 Cal.App.4th 1196, 1206, fn. 1, 184 Cal.Rptr.3d 461 (conc. opn. of Bamattre-Manoukian, J.).)
The District Attorney says Senate Bill No. 1391 is unconstitutional because it amended Proposition 21 without the requisite two-thirds vote of each house. To the contrary, the provisions of Proposition 21 relating to the prosecution of 14- and 15-year-olds were repealed by Proposition 57, which eliminated Proposition 21's direct-filing procedure. ( People v. Superior Court (Alexander C.) (2019) 34 Cal.App.5th 994, 1004-1005, 246 Cal.Rptr.3d 712 ; see J.N. v. Superior Court (2018) 23 Cal.App.5th 706, 710-711, 233 Cal.Rptr.3d 220.)
The District Attorney argues Proposition 57 modified Proposition 21 (which, he agrees, was constitutionally allowable) by eliminating the ability of prosecutors to directly file charges against juveniles in criminal court, and by altering the factors to be considered in transferring a juvenile to adult court. He says, however, that Proposition 57 did not eliminate the juvenile court's power to transfer 14- and 15-year-olds to criminal court. This authority to transfer 14- and 15-year-olds was not enacted as part of Proposition 21, however, but rather became law on January 1, 1995, as the result of Assembly Bill No. 560. ( § 707, former subds. (d), (e), as amended by Stats. 1994, ch. 453, § 9.5.) The question is whether Senate Bill No. 1391 unconstitutionally amends Proposition 57, not Proposition 21. As we held in T.D. , it does not.
II
Senate Bill No. 1391 is not unconstitutionally vague.
The District Attorney next contends Senate Bill No. 1391 is unconstitutionally vague, because it rewrites section 707, subdivision (a) to make it unclear to victims, defendants, the police, and prosecutors when a 14- or 15-year-old can be tried in criminal court. Specifically, he points to section 707, subdivision (a)(2), which now provides, in pertinent part: "In any case in which an individual is alleged to be a person described in Section 602 by reason of the violation, when he or she was 14 or 15 years of age, of any *391offense listed in subdivision (b), but was not apprehended prior to the end of juvenile court jurisdiction, the district attorney or other appropriate prosecuting officer may make a motion to transfer the individual from juvenile court to a court of criminal jurisdiction." The District Attorney argues that when section 707, subdivision (a)(2) is read in conjunction with sections 607 (concerning the retention of and discharge from juvenile court jurisdiction) and 663 (concerning when an arrest warrant can be issued for a minor), it "creates confusing law and encourages arbitrary and discriminatory enforcement." This is so, he says, because 14- and 15-year-olds are unlikely *165to understand the "vast difference in liability" they will face if apprehended immediately versus if they abscond until after the expiration of juvenile court jurisdiction, and law enforcement "may be encouraged not to solve crimes or not to catch fugitives because a minor's liability will be greater, if law enforcement waits until the minor is no longer eligible for juvenile court jurisdiction."
" 'The rule is well established ... that one will not be heard to attack a statute on grounds that are not shown to be applicable to himself and that a court will not consider every conceivable situation which might arise under the language of the statute and will not consider the question of constitutionality with reference to hypothetical situations.' [Citation.]" ( Tobe v. City of Santa Ana (1995) 9 Cal.4th 1069, 1095, 40 Cal.Rptr.2d 402, 892 P.2d 1145.) The District Attorney does not dispute that I.R. was apprehended within days of the homicide, well before juvenile court jurisdiction expired. Thus, the District Attorney is asking us to consider the question of constitutionality with reference to hypothetical situations, without explaining why we should do so or how he has standing to raise the issue. Accordingly, we reject his claim.
We also reject his claim on the merits. "Vagueness may invalidate a criminal law for either of two independent reasons. First, it may fail to provide the kind of notice that will enable ordinary people to understand what conduct it prohibits; second, it may authorize and even encourage arbitrary and discriminatory enforcement. [Citation.]" ( City of Chicago v. Morales (1999) 527 U.S. 41, 56, 119 S.Ct. 1849, 144 L.Ed.2d 67.)
We turn first to the "fair notice" prong. "It is a fundamental tenet of due process that '[no] one may be required at peril of life, liberty or property to speculate as to the meaning of penal statutes.' [Citation.] A criminal statute is therefore invalid if it 'fails to give a person of ordinary intelligence fair notice that his contemplated conduct is forbidden.' [Citations.] So too, vague sentencing provisions may pose constitutional questions if they do not state with sufficient clarity the consequences of violating a given criminal statute. [Citations.]" ( *392United States v. Batchelder (1979) 442 U.S. 114, 123, 99 S.Ct. 2198, 60 L.Ed.2d 755.) However, " '[i]t is impossible, given the complexities of our language and the variability of human conduct, to achieve perfect clarity in criminal statutes. Reasonable specificity exists if the statutory language "conveys sufficiently definite warning as to the proscribed conduct when measured by common understandings and practices." [Citations.]' [Citation.] ' "[S]tatutes are not automatically invalidated as impermissibly vague simply because difficulty is found in determining whether certain marginal offenses fall within their language. [Citation.]" [Citation.]' [Citation.]" ( People v. Hagedorn (2005) 127 Cal.App.4th 734, 746, 25 Cal.Rptr.3d 879.) " 'All presumptions and intendments favor the validity of a statute and mere doubt does not afford sufficient reason for a judicial declaration of invalidity. Statutes must be upheld unless their unconstitutionality clearly, positively and unmistakably appears.' [Citation.]" ( People v. Garcia (2014) 230 Cal.App.4th 763, 768, 178 Cal.Rptr.3d 883.)
Section 707, subdivision (a)(2), as amended by Senate Bill No. 1391, meets these requirements. A 14- or 15-year-old who commits an offense listed in section 707, subdivision (b), but who is not apprehended prior to the end of juvenile court jurisdiction, faces potential prosecution as an adult. That the differences in liability between the juvenile court system and the criminal court system require reference to *166other statutes, does not make the statute in question unconstitutionally vague. Moreover, the standard set out by the United States Supreme Court refers to the understanding of " 'a person of ordinary intelligence' " ( United States v. Batchelder , supra , 442 U.S. at p. 123, 99 S.Ct. 2198 ), not the understanding of a 14-year-old, as posited by the District Attorney.
The District Attorney fares no better with respect to the arbitrary/discriminatory enforcement prong. We categorically reject the suggestion law enforcement officers may intentionally "not ... solve crimes or not ... catch fugitives" so as to increase a minor's liability. That a minor's punishment may, under certain circumstances, be based on when he or she is apprehended rather than the type of crime he or she committed, does not make the statute vague.
III
Senate Bill No. 1391 applies retroactively.
The District Attorney observes that the text of Senate Bill No. 1391 does not address retroactivity, and there is a presumption that laws apply prospectively only. He recognizes that in Lara , supra , 4 Cal.5th at page 308, 228 Cal.Rptr.3d 394, 410 P.3d 22, the California Supreme Court held that because Proposition 57 ameliorated the possible punishment for a class of persons - juveniles - an inference of *393retroactivity applied. He argues, however, that in the case of Senate Bill No. 1391, the Legislature had the "clear option to explicitly state" the statute applies retroactively and failed to do so. Although the District Attorney does not expressly state the conclusion he would have us draw, it appears he is claiming Senate Bill No. 1391 should not apply retroactively to juveniles like I.R., whose alleged offenses were committed before the statute's effective date.
The District Attorney's position lacks merit. He provides no reason whatsoever for applying Senate Bill No. 1391 differently than Lara requires us to apply Proposition 57: retroactively "to all juveniles ... whose judgment was not final at the time it was enacted." ( Lara , supra , 4 Cal.5th at p. 304, 228 Cal.Rptr.3d 394, 410 P.3d 22.) "The Legislature, of course, is deemed to be aware of statutes and judicial decisions already in existence, and to have enacted or amended a statute in light thereof. [Citation.]" ( People v. Harrison (1989) 48 Cal.3d 321, 329, 256 Cal.Rptr. 401, 768 P.2d 1078.)
IV
The murder case against I.R. cannot be transferred to criminal court based on the felony I.R. allegedly committed when he was age 17.
The District Attorney contends that even if I.R. should not have been transferred to criminal court based on the homicide alone, he - and the murder charge - were properly transferred based on the separate felony assault he allegedly committed when he was 17 years old. Relying on section 707.01, subdivision (a)(3), which was not changed by Senate Bill No. 1391, the District Attorney reasons the assault case was properly transferred to criminal court8 ; murder is an offense listed in section 707, subdivision (b) and so is a proper subject for transfer; hence, the juvenile court has jurisdiction to transfer I.R. to adult court on all charges. We disagree.
*167Section 707.01, subdivision (a)(3) provides: "(a) If a minor is found an unfit subject to be dealt with under the juvenile court law pursuant to Section 707, then the following shall apply: [¶] ... [¶] (3) All petitions pending against the minor shall be transferred to the court of criminal jurisdiction where one of the following applies: [¶] (A) Jeopardy has not attached and the minor was 16 years of age or older at the time he or she is alleged to have violated the criminal statute or ordinance. [¶] (B) Jeopardy has not attached and the minor is alleged to have violated a criminal statute for which he or she may be presumed or may be found to be not a fit and proper subject to be dealt with under the juvenile court law."
*394Without explanation, the District Attorney asserts section 707, subdivision (b) conflicts with section 707.01, subdivision (a)(3) and then concludes that, because murder is a section 707, subdivision (b) offense, it "is a proper subject for transfer."
We recognize I.R. was 16 years of age or older at the time he allegedly committed felony assault, rendering transfer of that offense permissible pursuant to section 707, subdivision (a)(1), even after enactment of Senate Bill No. 1391. Additionally, murder is a transferrable offense. ( § 707, subd. (b)(1).) I.R. cannot, however, be transferred on the murder charge under either section 707.01 or section 707 because he was under 16 years of age at the time he allegedly committed it.
If a minor is found to be an unfit subject to be dealt with under juvenile court law pursuant to section 707, then we believe section 707.01, subdivision (a)(3)(A) requires transfer of all pending petitions where the minor was 16 or 17 years old at the time of the offense(s) alleged in those petitions. Had the Legislature intended transfer of pending petitions to occur whenever the minor was 16 years of age or older at the time of any alleged offense, presumably that body would have used the indefinite "a" with regard to "criminal statute."9 Because the Legislature did not, I.R. does not meet the requirement of section 707.01, subdivision (a)(3)(A) with respect to the homicide and related charges and allegations. Post-Senate Bill No. 1391, subdivision (a)(3)(B) of section 707.01 does not apply to a minor under age 16 at the time of the offense, unless he or she was not apprehended prior to the end of juvenile court jurisdiction. ( § 707, subd. (a)(1) & (2).) I.R. does not meet this requirement. Moreover, as we have explained, I.R. is now alleged, post-Senate Bill No. 1391, to have violated a criminal statute for which he may not be found to be unfit for juvenile court jurisdiction. Accordingly, section 707.01, subdivision (a)(3)(B) requires the petition arising out of the homicide to be disposed of in the juvenile court pursuant to the juvenile court law.
Even aside from the grammatical construction of section 707.01, subdivision (a)(3), prohibiting transfer of I.R.'s murder case comports with legislative intent. That intent, as clearly expressed by Senate Bill No. 1391, is to have 14- and 15-year-olds *168adjudicated - no matter the offense(s) alleged - in the juvenile court. *395DISPOSITION
The order to show cause previously issued is discharged, and the petition for writ of prohibition and/or mandate is denied. The stay issued by this court on March 4, 2019, shall remain in effect only until this opinion becomes final in all courts in this state or the California Supreme Court grants a hearing, whichever shall first occur; thereafter said order is vacated and said stay is dissolved.
I CONCUR:
PEÑA, J.