Son, at 18 you'll be big enough to leave home and strike out on your own. You will be mature enough at 18 to get your driver's license. At 18 you'll have learned enough about life to contribute your conscientious vote at the ballot box. And at 18 you'll be mature enough to sacrifice life or limbs in service to your country. So I can decide at 18 if I want to try a cigarette? Oh hell no, you'd be too young!