delivered the opinion of the court:
In December 1981, defendant Joseph Young appealed his convictions and sentence for murder and armed robbery to this court. Thereafter, in an order pursuant to Supreme Court Rule 23 (87 Ill. 2d R. 23), this court affirmed the convictions, but remanded the case to the trial court for reconsideration of the sentence. On remand, the trial court reimposed the same sentence: a term of natural-life imprisonment on the murder conviction and a concurrent term of 60 years on the armed-robbery conviction. Defendant again appeals, arguing: (1) the trial court’s refusal to consider evidence of his activities since his first sentencing hearing violated his constitutional and statutory rights; (2) his sentence should be reduced by this court in light of his rehabilitative potential; (3) the imposition of an extended-term sentence for armed robbery violated the Uniform Code of Corrections (the Code); and (4) if this court remands the case for a new sentencing hearing, it should be remanded to a different judge.
The record shows that following a bench trial, defendant was convicted of the strangulation murder of a 63-year-old woman who was the mother of defendant’s former stepmother. Defendant’s written confession had been admitted into evidence at trial. In his confession, defendant stated that he left his house, taking with him an electrical extension cord, and went to the victim’s house intending to strangle her. He was invited into the home by the victim, ate lunch with her, and then walked up behind the victim and strangled her by putting the electrical cord around her neck and holding it there for five minutes. Defendant’s statement was corroborated by physical evidence and testimony of his friend who helped him remove items from the victim’s apartment the day following the murder.
The record also shows that in 1977, prior to the instant offense, defendant had been adjudged delinquent and placed on nine months’ juvenile probation for the aggravated battery of a mentally handicapped female. The victim in that case was stabbed with a butcher knife and suffered more than 50 lacerations to her head and hand. She ultimately lost the use of two fingers as a result of the attack. Defendant was 16 years old at the time of the stabbing. Thereafter, in 1980, defendant was convicted of residential burglary and placed on two years’ felony probation. Defendant was released on probation for the burglary when he committed the present murder.
In our prior Rule 23 order affirming defendant’s murder conviction, this court reviewed defendant’s criminal history and found that defendant “has very little, if any, potential for rehabilitation.” We nevertheless remanded the cause for reconsideration of defendant’s *363sentence in view of the defendant’s youth and the fact that the sentence carried no possibility of parole. See Ill. Rev. Stat. 1981, ch. 38, par. 1003 — 6—3(a)(2).
On remand, at the hearing to reconsider the sentence, defendant filed a written motion urging the court to consider evidence of his behavior subsequent to the initial sentencing hearing. The trial court denied the motion, but allowed defendant to introduce evidence of his good prison conduct and rehabilitative potential in order to make a record for this appeal.
At the hearing, Donald Wasson, a Pontiac Correctional Center educator who had taught defendant English and social studies at the institution, described defendant as an “excellent student.” He testified that defendant had become quite interested in religion and that he believed defendant could be rehabilitated. Wasson, however, admitted he had not been aware of defendant’s aggravated battery of a mentally handicapped girl.
Defendant also called as a witness William Singleton, superintendent of industry at Pontiac Correctional Center. Singleton testified that defendant had been working in the prison’s sheet metal plant for approximately eight months. He stated that he would hire defendant for his own business, if he had one, outside of prison. Singleton also admitted, however, that he did not know the details of defendant’s prior stabbing.
Marla Sims, the mother of defendant’s three-year-old daughter, testified that defendant sends home $20 every two months for their daughter’s support. He also writes letters, and she visits him at the prison. Marla Sims’ mother, Lois Sims, testified she keeps in contact with defendant and spoke of his increased interest in religion.
To complete his offer of proof, defendant introduced four letters from the prison staff and six letters from teachers. The letters indicated that defendant has adapted well to prison life and has behaved in a polite and courteous manner.
After hearing arguments, the trial judge stated that he knew defendant was 20 years old at the time of the sentencing and had considered that fact when he initially sentenced him. The judge further stated that he had considered defendant’s history and background, noting that defendant had a history of “preying” on the elderly and infirm, and that his crimes were escalating in nature. The court reviewed the details of defendant’s murder of a “63-year-old woman who considered him [defendant] and treated him as her grandson,” and observed:
“This, to me, indicates somebody who has a history of violence. *364It indicates to me somebody who has a propensity to reap that violence on the weak and the aged and the affirm [sic], and it is one who has not accepted any potential for rehabilitation that somebody else has shown in him.”
The judge then reaffirmed the sentences.
On appeal, defendant argues first that the trial court should have at least considered the proffered evidence of rehabilitative potential since the initial sentencing hearing. Our State constitution and the Unified Code of Corrections mandate that penalties be determined according to both the seriousness of the offense and the rehabilitative potential of the offender, with the intent to restore him to useful citizenship. (Ill. Const. 1970, art. I, sec. 11; Ill. Rev. Stat. 1985, ch. 38, par. 1001 — 1—2.) In our prior Rule 23 order, we found that the record indicated that defendant has very little, if any, potential for rehabilitation, but remanded for resentencing in view of defendant’s age and the preclusion of parole. This court specifically declined to exercise its power to reduce or vacate the sentence.
On remand, the trial court acted in accordance with the mandate of this court. The court reconsidered the sentence in view of defendant’s age and the preclusion of parole, and reaffirmed the same sentence. We note that even if this court had vacated the original sentence, the trial court would still not have been required to consider the behavior of defendant during his incarceration. In this regard, the Code provides that where an original sentence has been vacated, the trial court shall hold another sentencing hearing which “may include evidence of defendant’s life, moral character and occupation during the time since the original sentence was passed.” (Emphasis added.) (Ill. Rev. Stat. 1985, ch. 38, par. 1005 — 5—3(d).) Hence, the language of the statute is discretionary, not mandatory.
The recent Supreme Court case, Skipper v. South Carolina (1986), 476 U.S. 1, 90 L. Ed. 2d 1, 106 S. Ct. 1669, does not mandate consideration of a defendant’s good prison conduct in this case. Skipper held that in a death sentence case it is reversible error for a court not to consider post-arrest behavior at a sentencing hearing. The court reasoned that in a death sentence case a defendant’s prison conduct is highly probative of his ability to function in a structured environment. Such evidence could weigh heavily in the jury’s decision to impose the death sentence or natural life in prison and accordingly should be presented.
The Supreme Court in Lockett v. Ohio (1978), 438 U.S. 586, 604, 57 L. Ed. 2d 973, 990, 98 S. Ct. 2954, 2964-65, highlighted the difference between the factors to be considered in a capital case and a case *365involving a sentence for a term of years or life imprisonment. Lockett recognized that in a capital case “the sentencer *** not be precluded from considering, as a mitigating factor, any aspect of defendant’s character or record *** as a basis for a sentence less than death.” (Emphasis in original.)
We further observe that even though the trial court indicated during the hearing that it would not consider evidence of defendant’s good prison conduct, the record shows that the court ultimately did consider such evidence when it stated:
“All that has been shown to me here today is that Mr. Young has demonstrated a capacity to function in a structured society, whereas he did not demonstrate that capacity in an open society. And this is absolutely in keeping with my original sentencing determination.”
Thus, the trial court did in fact take into account the evidence of rehabilitation offered by defendant at the hearing. Accordingly, we find no error as to this matter.
Defendant further argues that this court should reduce his sentence in light of the evidence adduced at the hearing. It is held that the trial court is in the best position to assess and weigh all factors relevant to sentencing and unless an abuse of discretion can be shown, the reviewing court will not disturb a defendant’s sentence. People v. La Pointe (1981), 88 Ill. 2d 482, 492-93, 431 N.E.2d 344, 348-49.
Next, defendant argues that the trial court erred in imposing an extended-term sentence for his armed-robbery conviction because it violates the extended-term statute. Defendant made no objection on this basis at the time of sentencing and the question was not raised in a motion for a new trial. Nor was the issue raised in defendant’s initial appeal of his conviction and sentence. The issue now presented is raised for the first time on this second appeal and is therefore waived for review. In re Lamb (1975), 61 Ill. 2d 383, 387, 336 N.E.2d 753, 756.
Even if this issue had not been waived, we nevertheless find no merit to defendant’s claim. The extended-term statute provides:
“A judge shall not sentence an offender to a term of imprisonment in excess of the maximum sentence authorized by Section 5 — 8—1 for the class of the most serious offense of which the offender was convicted unless the factors in aggravation set forth in paragraph (b) of Section 5 — 5—3.2 were found to be present. Where the judge finds that such factors were present, he may sentence an offender to the following:
(1) for murder, a term shall be not less than 40 years and *366not more than 80 years;
(2) for a Class X felony, a term shall be not less than 30 years and not more than 60 years; ***” (Ill. Rev. Stat. 1981, ch. 38, par. 1005 — 8—2(a).)
Defendant argues that the statute does not permit an extended-term sentence for his armed-robbery conviction because that offense is not in the class of the most serious offense of which he was convicted, murder.
An argument similar to the one now before us was recently addressed by our supreme court in People v. Neal (1985), 111 Ill. 2d 180, 489 N.E.2d 845, cert, denied (1986), 476 U.S. 1165, 90 L. Ed. 2d 733, 106 S. Ct. 2292. In Neal, the defendant was sentenced to death for a murder conviction and received an extended-term sentence for the lesser offense of armed robbery. There, as here, the defendant argued that the statute does not allow an extended-term sentence for armed robbery since that offense was not in the class of the most serious offense of which he was convicted. The supreme court rejected that argument, reasoning as follows:
“The defendant’s contention would be valid if he had been given an extended-term sentence of imprisonment on the murder conviction. (See People v. Jordan (1984), 103 Ill. 2d 192, 203-06.) The sentence here, however, was not for a term of years. A death sentence was imposed, and the extended-term statutory provision was not applicable.” (111 Ill. 2d 180, 204, 489 N.E.2d 845.)
Here, as in Neal, defendant was not given an “extended-term sentence” on the murder conviction as that term is used in the statute. The extended-term sentences set forth in the statute are all for a term of years. (See Ill. Rev. Stat. 1985, ch. 38, par. 1005 — 8—2(a).) In this case, defendant’s sentence of life imprisonment without possibility of parole is not a sentence to a term of years, but is by its very nature a sentence of undetermined length. Accordingly, under Neal, we find that the imposition of the extended-term sentence for the armed robbery was not precluded in this case by statute.
Given our disposition above, we need not consider defendant’s remaining argument that if the cause is remanded for a new sentencing hearing it should be remanded to a different judge.
For the foregoing reasons, the judgment of the circuit court of Cook County is affirmed.
Affirmed.
*367CAMPBELL, J., concurs.