To enter into a contract - 18 To get married without parental permission - 18 To purchase alcohol - 21 I am assuming that you are asking about "age of consent", for the purpose of knowing your rights as a young adult, perhaps in reference to dating or family issues. I always thought that age of consent was pretty much straight forward. Well, it isn't! Each state has more than one definition for "of age". It may depend on the age difference of a dating couple. Some are 18 yrs. with someone less than 14 yrs. and call it statuatory rape. Then there are ages for informed consent, impairing the morals of a child, being romantically involved with a younger person whom you have authority over...on and on and on. And the ages change for each situation. I'm posting a website to check on legal age of consent in each and every one of the 50 states. It's very informative and detailed.