Animation and motion graphics has been my bread and butter, but I also have solid drawing skills that I call on daily for those jobs (though I could always be better and there are those who draw circles around me).
I'd love to break into serious illustration jobs more consistently, but no luck so far. But the few I've had have been fun if not challenging for their tight deadlines.
It's pretty competitive in all art fields, and the idea of "better pay" is a joke, imho.
Clients vary, some allow far more creative freedom simply because they dig your stuff or they have no idea what they want till you present them with options. Then they begin to nitpick until they realize you're gonna bill them for revisions or the deadline is too tight to make changes.
Others know exactly what they and won't settle for less while still giving you the freedom to add your own take to things.
I've been fortunate to have all sorts of clients and while it can be frustrating, I end up learning a lot about my craft I wouldn't have otherwise, so it balances out.
At least, that's how it is for me.
The challenge for me is realizing when I'm working for others, I'm not an artist but a hired hand. Which is why I use my down time to work on personal projects.
My advice - since you're in high school, I'd emphasize anything that stressed classic hardcore drawing and take as many design electives as you can on the side. Learn it all. There may be a minimum, but there is no maximum, so take on as much as you can handle.
College is another story, and I'd suggest majoring in anything where a decent paycheck is guaranteed - medicine, engineering, etc. No one cares about your degree in art, just your portfolio and majoring in art is probably the best way to rack up debt you'll never pay off.