(1) Notwithstanding any other provision of law, the penalty for any person convicted of a Class IA felony for an offense committed when such person was under the age of eighteen years shall be a maximum sentence of not greater than life imprisonment and a minimum sentence of not less than forty years' imprisonment.
(2) In determining the sentence of a convicted person under subsection (1) of this section, the court shall consider mitigating factors which led to the commission of the offense. The convicted person may submit mitigating factors to the court, including, but not limited to:
(a) The convicted person's age at the time of the offense;
(b) The impetuosity of the convicted person;
(c) The convicted person's family and community environment;
(d) The convicted person's ability to appreciate the risks and consequences of the conduct;
(e) The convicted person's intellectual capacity; and
(f) The outcome of a comprehensive mental health evaluation of the convicted person conducted by an adolescent mental health professional licensed in this state. The evaluation shall include, but not be limited to, interviews with the convicted person's family in order to learn about the convicted person's prenatal history, developmental history, medical history, substance abuse treatment history, if any, social history, and psychological history.