What age does a girls goons stop growing?

It depends. usually, when you start to grow pubic hair, that is about the same time breasts(or goons, how you say it) grow. when do they stop? probably when you finish your period. relax, don't freak out. it's a cycle of life. the age...it depends when you first get your period and when it ends. anyways, hope I satisfied you with this answer.