My very first piece of mail during Cadet basic training at West Point....a threatening letter from the government saying I needed to register.
Even though I was in the army two months after turning 18, I had indeed registered for the draft (and have since checked and verified that it is all in order).
But for some reason, systems failed and I got the letter :(
Classic. They should have sent you a letter threatening to have you court martialed for not registering!