Few endeavors, if any at all, I find to be inherently mature or inherently immature. Maturity is neither defined by one's particular preferences nor by one's particular activities; rather, it is defined by the strength of one's character.
Criss Jami, Healology
activity, adult, character, child, childish, childlike, development, endeavor, fun, immaturity, leisure, maturity, playing, psychology, responsibility, toys, traits, venture, video-games