Chalts, what is legally an adult in America? 18? And what exactly can you do at 18 that you can't do when you're seventeen? I'm English and here it's 16 to smoke, gamble, have sex, move out on your own and quit school if you want, and basically be an adult (sign contracts, etc, etc) and it's 18 to drink and vote. Of course, thiese age limits really mean nothing beacuse everybody does most of these things waaaayy before the legal age.