If you want to continue your high school python learning outside of school, you can try a web framework like flask or Django, with Django being my favorite.
As you've been learning javascript, you could learn express with nodejs, which allows you to make an API using javascript.
For Java, you could learn something like Spring, but it's probably best to not try and do 3 languages at once.
There a couple of ways.
This is just my 2 cents, best of luck!
Thank you for your advice!