About the changing room thing: Talk to your guidance counselor. That's what they're there for. Ideally, call the school and see if you could meet with them before school starts. If that's not possible do it first day back. In general it's good if they know about the change and can be prepared for things that might come up during the school year. And they probably already have solutions for issues that are to be expected (like the changing room thing, bathrooms, how to avoid bullies,...). Good luck with everything! ♥️