If its USMC you need to do 3 pull ups, run 1.5 miles in under 12 minutes (my recruiter told me it was 1 mile, but in boot camp our initial physical fitness test was 1.5), and i think 50 sit ups in 2 minutes. Im not sure about the sit ups, but that was real easy. As long as you can do that you can phycially complete boot camp. But the psychological aspect is so much more to worry about.
whatever you do, dont faint or give up. you'll get what we call the Silver Bullet lol. and drink alot of water otherwise you will faint. and for morning chow dont drink milk especially on PT days
If its Army, it shouldn't be difficult at all. I had a friend we called Herbert, and he was 5'11, 110 pounds and weak as hell and he completect Army basic training.
But even if you go and are not in good enough shape they send you to PCP which stands for Physical Conditioning Platoon which is part of STC (Special Training Company) and we called it Pork Chop Platoon because they were all fat-bodies. Then once you are in good shape they send you to another Company where you start off again. Sometimes you dont have to restart from TD-1 though.