Legal adult means they register for selective services, can buy lottery tickets, and be charged as an adult in a crime (big one for me). I don’t think that 21 is the federal drinking age, but a state law. Thanks to MADD states who have a lower drinking age than 21 won’t receive federal funds for roads. Ironically generation X’rs are the least likely to drink and drive, at least the ones I know. I do not agree with it.