https://www.academyadmissions.com/requirements/academic/
Go ahead and give that page a look... In fact, if you haven't read the entire website, start working on that too.
The gist of your high school course load should look like this:
- Conforms closely to the recommendations on that page
- Usually composed of the most challenging equivalents of each course (AP, IB, Honors, etc.)
- Has academic electives sprinkled in here and there
- Doesn't see any repeated core classes due to failing grades
Honestly, in my experience here, your high school schedule needs to be thought out carefully, but it should also be fairly intuitive. You do need to challenge yourself in your course load and excel at the tough classes. If your school offers Physics and AP Physics, go AP. US History vs AP US History? Go AP US History. Usually, I see appointees having taken 6-8 AP courses over their four years, and some honors courses on top of that.
That being said, if you know you can't handle a course, don't sign up for it. An A in Algebra is way better than a D in Calculus. The Academy wants to see you challenge yourself, and excel at the tough courses. But they don't want to see you take 17 AP courses and fail all of them.
As for electives, have fun with your choices. Take classes that will give you that little break, classes which you find enjoyable and look forward to. Sure, you should take a few academic electives like Comp Sci, but also do some non-academic ones as well. USAFA doesn't look at your non-academic electives.
You've got four years to build your package. That's plenty of time to nail down everything you need. You're on a great path as of right now. JROTC and Band are great electives. But you only get to do high school once. Don't look back after graduation and regret how you never took any fun classes. If you succeed in your core academics, that one elective isn't going to have much of an impact in either direction.