You should seriously consider staying out of the military, even if you think you can get in. It doesn't sound like you would be a good fit (I was in the military myself so I know what the physical demands are). Please understand, I say this out of kindness and concern. There are always alternatives; the Civil Air Patrol, the Peace Corps, AmeriCorps, CityYear, etc. There are lots of different ways to serve your country and the world.