Why does it take so long to recover after i go to the gym?

Ok, so im a 16 yr old chap, 130 pounds (60kg) and 5'11" (if this helps). Anyway, I do mainly compound exercises in the gym (such as bench press, squats and dead lifts), and i don't do any of those easy exercises which seem to look nice when looking at the mirrors lol. However, i take around 4-5 days to recover as my muscles ache for this time. i would like to know why because my friends take 2-3 days. I also have 7% body fat (if that helps any further) and am quite skinny. Thanks in advance!