When will I grow pubic hair?

I'm fourteen and last time I checked, I have no pubic hair. I'm 6'0'', and my voice is deep, and I just don't have any hair on my body. My friends make fun of me, and rob their crotches in jest when I come up to them. They even gave me a pubic comb for my birthday! Can someone tell me when I'll grow my pubes? I've tried Rogain.