I think all citizens should have to go through the military’s Basic Training when they hit 18. No need to do the 4 years of service if they don’t want to, but do have to make it through boot camp, even if you want to go to university.
I dunno... being trained in individual and squad movement tactics might come in handy over the next 4 years. Firearms training too, that in restricted states can let you skip classes you'd otherwise pay for is cool too, and would be handy for a lot of peeps.
Not really talking about the guns part. More the working out, the team building, the discipline. When I did basic training we only had like 1 or 2 days for training with guns. I was in the navy tho.
All of those can be taught in a civilian way, ideally in school. As much as I personally hate exercising, schools do need more PE and more sports and civil service events that would tie people together. Discipline, too, is part of a solid school background, although, and this is the problem with the army too, it must not be confused with obedience.