Reddit reviews The Physical Universe: An Introduction to Astronomy (Series of Books in Astronomy)

This is definitely above your level, and it's from 1982 so it's a little outdated, but if you're really interested in astrophysics then it might be worth checking it out and trying to work through at least the first few sections. I think it's written so that you can follow it without too much math involvement.

Frank Shu - The Physical Universe: An Introduction to Astronomy

Otherwise, there are a lot of great popular-writing (i.e. not a textbook) books about physics/astrophysics. Here are a few:

Stephen Hawking - A Brief History of Time

Carl Sagan - Cosmos

Neil deGrasse Tyson - Death By Black Hole, and Other Cosmic Quandaries

My biggest advice, though, for taking physics in high school is to try to do as well as you possibly can in your math classes. Those are the most important for getting into physics. If you do well in math then physics should be pretty easy.

It's a bit old so won't discuss many of the more recent findings, but the absolute best undergraduate astrophysics book I know of is Frank Shu's The Physical Universe. I worked through the whole book studying for my prelims in grad school. :-)

The Physical Universe by Frank Shu, is probably one of the best books out there on Astronomy. It's technical enough to get you to a level where you can begin to comprehend current research at some level, but accessible enough so it doesn't need more than some basic math, physics. The range of topics is amazing too, everything from black holes to astrobiology.

Only downside ? Its 80$, but this book will last you a lifetime and you can grow old reading it to your grandkids...