A simple checklist could have helped a prosecutor in Peoria County’s Juvenile Court avoid a big blunder during S.M.’s trial on a charge of unlawfully possessing a firearm in violation of Section 24-3.1(a)(1) of the Criminal Code of 2012.One of the things the state had to prove during the adjudicatory hearing was that S.M. was a minor. Under Section 24-3.1(a)(1), “A person commits the offense of unlawful possession of firearms or firearm ammunition when: (1) He is under 18 years of age and has in his …