im 16, im fat 5'9 234 pounds, anyway, when i put a condom on, it dosnt use up the whole condom, so i cant unroll it all the way or else it would bunch up and there would be alot of extra space, is that normal

Hey bud, thats fine, happens to me too. Condoms are made to fit different length penises, thats the reason for some "left over" at the bottom. Main thing is that you put it on correctly and make sure it stays tight, you're right, if you unrolled it all..you'd end up with bunching and that could cause it to rip and you DON'T want that to happen.