I haven't hit puberty, I am 16. I have pubic hair. One of my testicles is nearly double the size of the other which scares me.?

Sounds like you. have it puberty. That's what pubic hair is all about. You probably have a deeper voice, emerging facial hair, broadening shoulders, elongation of limbs and facial bones, etc. A larger testicle isn't by itself such a big deal, unless it is painful, or causes dysfunction. But a check with your pediatrician wouldn't hurt.
See doctor. Actually, pubic hair is a sign of puberty. Testicular size is worrisome, since testicular cancer can occur in young men. See a doctor.