This is why sexualization is so insidiously dangerous. It completely trivializes the female, hanging all of her worth on the thin, gossamer thread of her sexual appeal. Age, gain weight, have small breasts, be smarter than you are pretty, and bang, there goes your value.
The main point is to see sexuality as a normal, natural part of life and development. Your child is a little person with an emerging sense of sexuality. Don’t be afraid of that, instead, approach those feelings and thoughts just like you do with anything else that they’re learning. When you think of it that way, it helps you take advantage of natural opportunities for conversation and sharing of information with your child.