if you try to buy beer, but don't use a fake id and never say you're 21 can you still get in trouble? if you just walked into a store, get carded, and left, can you still get charged?

It may be helpful to look at Arizona Revised Statutes 4-241(l) - (n)

L. A person who is under the legal drinking age and who misrepresents the person's age to any person by means of a written instrument of identification with the intent to induce a person to sell, serve, give or furnish spirituous liquor contrary to law is guilty of a class 1 misdemeanor.

M. A person who is under the legal drinking age and who solicits another person to purchase, sell, give, serve or furnish spirituous liquor contrary to law is guilty of a class 3 misdemeanor.

N. A person who is under the legal drinking age and who uses a fraudulent or false written instrument of identification or identification of another person or uses a valid license or identification of another person to gain access to a licensed establishment is guilty of a class 1 misdemeanor.