Well, I think you should consult your doctor to see if it's a safe/good idea. If it is, great, get to workin'. If not...well, work out and stuff, and it'll be cool to take a MA class or two for self-defense, and you can teach it later in your life. Most instructors aren't as good at fighting than they are at teaching anyway. (Some are, some aren't. As long as you know the material you're fine)
Good luck, bro.