Lots of assumptions here about the JAG, I have to ask Vagabond if he even wants to practice law in the military?

I know of a NYC dentist who is a Sgt in the Marine Corps. He is a machine gunner. Every drill they kept offering him to convert to Navy Officer to be a dentist and he finally said something to the effect of "I'm a dentist all week, this is my time to be a Marine. I'm here to shoot a machine gun, not work on teeth, so stop asking me." Here's a guy making a 6 figure income and he's proud and content to man a machine gun on the weekends.

My advice: If you want to serve, even late in life, then serve. Pick something you will have fun with and enjoy, and don't limit your options by your day job.