How hard is it to learn to be an effective defensive lineman at college level with limited experience?

I say go for it. Why the heck not? I'm sure people said you shouldn't go back to school at 27 either but so what. This is your life. The worst thing that will happen is that you will get your *** busted, but you'll have the great memories. The martial arts should really help with your balance and footwork. Heck, if you don't make the team, you might get on the staff and when the 'stars' are back home washing cars and dreaming about their glory days, you might just be on the front end of your career as an athletic director. Blog and write about your experience....sounds like it will be a gas....good luck...wear your cup!