Son, you need to see a doctor. I'm happy everyone wanted to make you feel better about your size, but it's by far, not your most pressing problem. The foreskin not going over the glans
and being too tight can be leading up to a major problem, You need to see a doctor and let him determine. It can if not dealt with, cause a loss of circulation, or eventually if over the top, close up and cause urinary issues. At 17, your penis is almost done growing, and the average male penis now is approximately 6 inches, learn technique to compensate, most women will prefer that better.