Military JAG/Future Lawyer Perhaps College Help Question?

I am currently in college, and im going after my business management degree. I want to enlist into the military. either the navy or Marine corps and pursue into the JAG program. I know i wont be doing the big boy stuff, but its a start. i hope this would be a good gateway into the civilian judicial system. i also understand that theres a difference between the civilian side and the military JAG system. Now my school up here doesnt offer anything law so what i was planning on doing was earning my business management or general business (what ever works best for Law; not sure). then after what should i do. i apologize if this is a large explanation/details. more than enough details needed. anywho. thank you. anything helps. have a nice day!