Is getting involved in strenuous exercise a bad idea for an adolescent girl?

I've read things about how size and vocal range are determined by how much estrogen a girl has while going through puberty, also, I have noticed that a lot of girls that are really evolved in athletics as a child grow up to have sort of a raspy voice and small , I've heard that excessive exercise increases testosterone in a girls body and lowers estrogen and that it actually changes the way that she develops