My Son Is 6 Years Old And Is I Think

My son is 6 years old and Is I think going threw puberty, I'm kind of nervous is this way too soon? He wants to eat so much, but I don't want him to become over weight. He has a lot of hair down there and on his legs but just a little under his arms. He has a very strong odor, I bought dove deodorant and that has helped. But at 6 all of this is going on....