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.

its normal for them to be all shapes and sizes dont worie too much its not the size that matters its all how you work it take it from a 23 yr old female who's with a smaller man now that i plan to marry... growing up i thought it mattered and all my bf's were guge  but i hurt and ever since ive been with my hubby now ive never had more satifation so dont worrie too much about men grow till there 23 and if when ur at that age if its still bothersome get a pump and do it yourself have confidence thats what  weman are attrcted to

There is nothing to boather about size and all. 4.5 intches is good enough. Regarding foreskin too hard and not opening up, do massage your penis gentely with musterd oil in a motion to open it up. It will slowly get ok but wait for atleast two years to see proper results as you are still at growing age.