It should not effect you joining the Air Guard. It will cause a suspension of your driving privilege for 90 days. You will have a fine and it will remain on your driving record.

If you get a citation in the mail, you should consider fighting this ticket. It is possible to have the penalty reduced to something that will not suspend your PA drivers license, and will not show on your driving record.

I only drank "whatever" is not an excuse. Being under 21 means that you can't even touch any alcohol, even being in possession is a violation that will suspend your license and leave a record.

Good Luck,
Vince