Sex, drugs, and alcohol arrests or convictions are the most likely offenses for which enlistment will be denied. As Mr. Driessen says, be honest with the recruiter. It's better to be declined than get caught later and prosecuted for fraudulent enlistment. And, keep in mind, this will affect you if you will need a security clearance for your AFSC. The SF 86 asks about alcohol related incidents going back seven years from the date of the application for clearance.