Why hasn't my penis grown?

I'm 14 and just starting to get long stringy pubic hairs. My penis grew about 2 inches in sixth grade. It used to be like always one inch when soft and now it's like 1.7 when soft and when hard it's like 3.1 inches. Why is my penis so small?!?! I have high school next year and we take showers and I don't want guys making fun of me for how small it is. Please leave your stupid idiotic immature comments out please if you're just goingto make fun of me. thanks