You've been charged with a misdemeanor, which is far less serious than being charged with a felony. Still, it is very important that you be represented by a lawyer any time you are charged with any crime. Even if future employers know about such an offense, it is not the kind of offense that most employers are going to be overly concerned about. Selling alcohol to someone under 21 is not like stealing or beating someone up or shooting heroin. There may be a youthful offender provision in the law that allows the record of this to be expunged. Any criminal charge is not good to have on your record, but this one is about as minor as it gets. But do talk to a lawyer, even if it is just a public defender assigned to you by the court. That can make all the difference in the world. Good luck.