I am no lawyer, but if I remember from my school days yes, that is a charge on your minor record, but the court deferred conviction due to surrounding circumstances. You can petition the court to erase your minor record, but as you have no convitions, provided you have nothing pending, there really is no need. Your minor record will be sealed, no convictions were made, legally you are good to go. Key is, how long have you not been a minor should you not be, and how long ago was the charge?
Now that doesnt mean it will be easy to get into the Army, as they do their own thing.