It is against the law for anyone under the age of 21 years old to purchase or consume alcohol. My child is 16 years old and smokes. The legal age for smoking is 18 years old. It is illegal for persons under 18 years old to purchase, possess, or consume any tobacco products. Yes, as long as you are not physically abusing your child.
Juveniles are subject to many additional legal restrictions.
This is not a comprehensive list of resources.