I'm in seventh grade and I want to learn more than I am?

I am extremely interested in astrophysics and astronomy and may get into algebra early next year but I don't feel lime I know enough, I want to know more about the big bang, relativity and gravity ( I'm also intersted in gas giant moons) I want to know how I can learn these things (books, whatever) I just feel constricted to my crappy school and the kids who refuse to listen to anything