Who called cannabis users immature? People of all ages smoke, and maturity has little to do with it. people like to get high.Always have, always will. The problem with using drugs as a teen is the immaturity of the brain. The younger a person starts using drugs the higher chance of developing an addiction, especially with certain types. My children started at 16-18, telling me afterwards, and they still smoke weed. One tried other things, but got away from them. I started at 17 also, and never let any of them become anything but an occasional thing, as working out and nutrition came first. All part of growing up is teens doing things their peers do, without the parents knowing most of the time. I don't judge anyone who gets high, as it's their life and up to them if they make it an addiction.