Courses to take in high school if I am interested in Robotics

What high courses should I take if I am interested in Robotics in my Junior year.
Please advise

Actually not only should you be taking rigorous stem classes such as physics and high level math but join a robotics team.

I started a robotics team in school but struggling to find a mentor, should I move to a winning team, sometimes I think
any advice?

Being part of a robotics team is about learning not winning. I would not worry about whether you are on a winning team. Keep looking for mentors. If you can’t find one join another one.