As an Army vet my only encouragement would be to tell your boy that I also wanted to be a Marine but they found out my IQ was too high so they sent me into the Army. :-)
(Heh-Heh, all in good fun)
He scored 97 on the ASVAB. 149/150 math. 147/150 GS. How did you do? (Just kidding. But... never mind)
Food for thought. We DID volunteer for it after all, rather than being shanghaied against our will.