Awh shi+...penis problems...?

Right so. My penis is only 1 inch unerect. And like 3 1/2 erect...I have facial hair. Pubic hairs and a lot of em. Voice is deep. And I haven't hit my growth spurt but I've grown about 3-4 inches but I still need to grow (only 5'4") and I'm 15. Yet my penis remains it's size. Why is this...? Halp