It's more than normal, don't worry. Testosterone is just doing its job and developing your body. In puberty hair grows on your body. It actually comes from the Latin word "pubescere" which means get covered in hair. For me it started when I was 13,hair growing suddenly on my legs and testicles.
It's different for everyone, for instance, one of my friends barely has hair on his legs and armpits, and he's 16 like me. It's normal, don't worry