What's important kinda depends on what you're interested in. If you wanna be an artist when you grow up, it's more important to develop your skills there than to learn about nuclear engineering. Unless you want to be both, I guess.

Really though, kid, I learned most of the stuff I needed to learn outside of school. Figuring out how to deal with people is way more important than being incredible at science.

[Says the ex-professor with two PhDs.]

But if you're really invested in learning as much school stuff as you can, go to libraries and research topics you wanna know more about, work your way up from there.