My sister is in Bnos Yaakov in 11th grade. She loves it. She’s a typical teenager. Not boy or movie obsessed but does watch movies and probably will sometimes talk about guys with her friends. But not in an unhealthy way.
Look, you’re going to get a group of those girls anywhere. And they are not good for your spiritual health. So just pick your friends wisely, anywhere you go.
I wish you the best of luck in picking the right high school. Bnos yaakov is an excellent school though.