That is a misdemeanor that could end with you having a permanent criminal record. It is unlikely that will receive any jail time if this is a first offense. You need an attorney.
Are you currently in contact with a recruiter for the Navy? If so, you should notify them of this because they will find it anyway. This will likely be a disqualifying event but you would need to discuss it with the recruiter. While a waiver is possible, it is unlikely at this time as the armed forces are still operating under a philosophy of lean budgets and staffing. If you are a highly desired candidate for whatever reason (intelligence, physical ability, aptitude for some difficult to fill field), that might save your bacon.

