I am in the military, doesn't give you any credit. For the most part the credit agencies have no idea what your profession is, nor do they care. When you request to get a loan they ask how much you make and that, along with your credit, is how they determine how much additional obligation against your credit they can take and give to you.

There are multiple factors to your credit, and one is a history of paying your on your credits. Starting that early is a good thing, although the car payment is probably not the best way to do so.

Keep the vehicle.

If no one will be driving the vehicle (family/friends) then talk to your insurance and tell them the situation. They can give you "storage" insurance (or whatever it's called), which is significantly cheaper.

Not sure if there is much you can do about the car payment. Keep the car lets you leverage your credit and begin building the credit history for future purchases.