@blossom gave the very solid steps to take, but @thumper1 pointed out a large potential pitfall that’s likely to affect this student: letting the paths of the older siblings affect this person’s experience. Anyone with this level of ability and effort is going to find a great place to continue her education. Kids like this succeed, but they aren’t always happy. Find out what she wants to study, let her see a broader variety of schools than the famous ones at the top of every list. Let her experience the different feels of campuses and students at more types of places. The risk of not getting into HYPSM might not be a risk at all if she falls in love with Bard or Claremont Mudd Scripps or Cal Tech or any other outstanding and unique school. In short, don’t settle for the famous name brands. As has been pointed out, it’s shocking how rarely any kid will be the smartest or dumbest person in the room. There’s a huge population of interesting, smart and energetic students attending most schools. Don’t let her be afraid to join them.