What classes should I take for my 15 credits for the Army?

I would take a simple math class if you feel rusty in that and then super easy classes like music history, PE, computer application(super easy). By the time you get out of the military, the credits will likely be expired anyway so it's not like you could use them if you did plan on college after.

If you don't plan on ever going to college then pick the academically easiest ones like physical fitness education or self defense or yoga 101 even underwater basket weaving if they offer it. Then there are useful certification classes like truck driving which could potentially help you in the future, or car mechanic type classes. If you have a knack for computers then consider a programming language or web design. If you do want to go to college some day in the future then ask your councilor about "general education classes" or something like that that every major has. Usually a few english composition courses, a social studies, history, art, diversity, etc. These may go towards a future college major. What you don't want to do is pick a course that is too hard, because if you fail then your enlistment gets set back many months.