Anyone heard of this?

I took my daughter for her 7yr check up today. They said she’s developing and growing right where she needs to be across the board. But she said that I might need to start looking into a sports bra for her because she’s starting to develop breasts buds now which is apparently normal and she said be on the look out for hair growth and she could start her period at 9.

Anyone else’s 7-9yr old went thru all that?