Wait until you've been accepted, then decide wether to go for it or not. If you've still got interviews ahead, you may be turned down anyway. If you get accepted, decide if you want to be in the Army or not. Visit a base, chat to people first hand, to help you make the decision.
Don't quit on the application process at this stage, as you will personally benefit from going though a selection process, even if you are turned down.
12 years is a very long time to do something, if you really don't want to be doing it.
ickle