She lives in a world that says being big is great for boys but embarrassing for girls. It's no coincidence that more than 90 percent of anorexia cases are female - unconsciously they're trying to stop growing. So let her know being taller means that people will look up to her more, and that's just as it should be. Help her admire women who aren't skinny or petite - basketball players, models, senators, yourself. And encourage her to play sports of all kinds - muscles are healthy and not a bit unwomanly.
Studies show that teen women who like math are more confident about their appearance.
They also worry less about other people liking them. This world needs vibrant, self-confident women, but it does its best to knock the stuffing out of them when they begin to grow up. You can help give young women the courage to challenge the lie that tells them they ought to shut up and sit down.