Synopsis As Introduced Amends the Criminal Code of 2012 and the Unified Code of Corrections. Eliminates mandatory sentences of natural life imprisonment for persons convicted of offenses committed before they attain 18 years of age. Provides that a person who was under 18 years of age at the time of an offense, may, after serving 15 years of his or her sentence of either life imprisonment or a term of 40 years or longer of imprisonment, submit a motion in the circuit court of the county in which he or she was originally sentenced for resentencing. Provides that the petitioner shall be eligible to file a second motion for resentencing not sooner than 10 years or longer than 20 years as determined by the court at the first resentencing hearing. Provides that the petitioner may file a motion seeking leave for resentencing upon reaching the age of 60. Establishes procedures and factors that the court shall use in considering the motion. Provides that on or after the effective date of the amendatory Act, when a person was under 18 years of age at the time of the commission of an offense, the court, at the sentencing hearing, shall consider specified factors in determining the appropriate sentence. Provides that no retroactive resentencing hearing shall be conducted until one year after the effective date of the amendatory Act. Provides that within one year of the effective date of the amendatory Act, the Illinois Juvenile Justice Commission shall present the General Assembly with evidence-based findings regarding the effects of sentencing minors as adults. Effective immediately.