Question about clubs and ap classes from an incoming freshman

1. Is it like the longer you stay in the club, the more you get promoted? Like if I just joined, sophomore year I can be the secretary and etc etc? Basically does loyalty mean higher ranks?

2. Different from topic but how should I practice for aps? I'm planning on taking them in sophomore but don't know which classes like history or biology or math.

3. Any good websites that can help me practice for aps or just class in general?

My classes right now are

Geometry

Biology 1

Exploring computer science

English 1

Mandarin 1

And that's pretty much it.

4th, theres like a class representative position for each homeroom. Will that have any impact on my transcript? Its not student council, just like a representative that speaks to the student council abt student issues or events etc.

5. Is khan Academy good? Im using it right now, any other websites that are like this, because Khan academy is great.

Thanks for taking your time to read this