Becoming an electrician (not sure if this is allowed here please remove if not)

So I’m currently in 8th grade going into 9th and I’ve joined my high schools polytech program on electrical. I was wondering what certifications I would need once I graduate and what ways to get them, I do get NCCER level 4, but I know I need more to become a apprentice then journeymen, what would they be and how would I get them? also do you guys know of books or website I can use to help me get a start on electrical before next year, I know the basics from helping my grandpa who me and him basically re-wired most of our house and working on 3D printers and other electronics but nothing more then the basics.