I truly believe Immerse is a great option. They are expensive, but they are also experienced and ready for multiple kinds of problems.
I went there last summer, and it was the most magical time in my life, the classes were helpful, but my teacher showed support, my mentor was always there to help us, and I met plenty of new friends that I'm going to take to life, and I got to know a new part of myself and be more clear about what I want in the Future.
And suppose you already know what you are going to do in college. In that case, it can be used as a supercurricular, since it is an activity that is about the chosen subject and surpasses the school curriculum. Besides, if you end up in a course that you like, but don't want to do this for your life, you made a significant discovery.
So, if you have the resources to go to Immerse's summer school, it will be an amazing time in your life and deeply change you.