Im sort of going through the same thing with my son. My boys 13 and has said for the last few months that he wants to join the army , he's said special forces but I imagine all young kids think that way .
I put a post up a few months ago about a weekend me and him did that was army centred where we went out and did missions which has had a real impact on him. Their was lots of military men running it out of the local gym and up in woodland and I think being around them has stoked his interest . He's only 13 so who knows how long his interest will last but he's a driven kid so it might