Question for anyone in the military.?

Last may I joined the DEP for the USMC(I ship out june 1, 08). I am now having second thoughts on joining. I don't mind going through boot camp or fighting a war that I believe in but, my problem is I don't support the war in Iraq and I don't want to risk my life for something I dont believe in. I'm almost positive I would be going to Iraq if I join. My MOS is more than likely gonna be Aviation Mechanics if it's available when the new fiscal year comes out. I am really interested in mechanics and am currently taking an auto service cl at a tech school. I'm thinking maybe I should just get out of the DEP and keep on going with tech school. So my question is... When you were in the DEP did you have second thoughts and almost drop out, but kept going with it? If so do you think joining was a better decision than not? I would really like to be a marine but I would also love to be an auto mechanic, I cant decide what to do.