Oh dude comeone, at your age your penis size is good at 5.7. I have seen dude with 4.5 and they are happy with it. In any case if you want to make your penis size bigger then take a look at these penis exercises
My dick is a solid six, I've been with over 20 women bout one of them have complained and none of my weeds has talked shit, unless you're dating loose pussy whores you need to swing that thing around like you're Babe Ruth with a baseball bat lol
You are of average size. Most gals are not hung up on cock size. Anything that is not abnormally small or huge is going to be fine. I'm 6 inches hard and never got a complaint. With todays porn - guys cocks appear the be HUGE .... due to camera angle and other factors.
Having a big dick is not all it is cracked up to be...if you tend to make your lover sore, or in the case of queer sex, they are flat out scared to accommodate you.
Enjoy your penis no matter how it is sized....your lover will appreciate it.