It's hard to see the physics competition now ... the physics competition is really difficult, and it is the most difficult competition. Unless you have a superior IQ and a good foundation, I suggest you consider it carefully.
3 The biological competition is slightly less difficult and can be considered. I don't know if the competition in your school will be dominated by classes ... in short, it will be better to learn more.
I don't know what the purpose of your competition is. If it's for interest or to broaden your knowledge, you can try for a while, or quit if you can't, and there will be plenty of time for the first year of high school. If it's to win the prize, forget it. Some competitions were sent to good universities, and some were delayed because of the competition, so it hurt feelings. Competition is different from college entrance examination. College entrance examination efforts must pay off, but competition is not. It's too dangerous to go this way.