If you don't care about college, then you don't need to worry about your GPA.
And if you don't care about college, make sure that you actually have a realistic plan for what you'll be doing after high school. There are all kinds of near-far/hyperbolic discounting/wishful thinking/self-deception -related issues where you might go from thinking "oh, college isn't really important" when you're starting high school and then realize "oh, but I don't actually have any realistic plan for no-college" near the end of high school, when the decision of what to do next actually becomes relevant.
Personally, the farther off I was from the point where I'd actually need to find a job, the more vague and ill-thought my plans for what I'd do at that point were. I went from "I'll just take whatever courses seem easy and interesting" in early high school, to "oh crap all the interesting career paths involve math which I haven't studied much" in late high school, to "I'll major in cognitive science and figure out some job later on" in early college, to "getting a job with just a cogsci degree is actually pretty hard, I'll switch my major to computer science for my Master's degree so I can actually get employed" in late college.
Even if you don't care about getting into college now, you might change your mind later on. If you maintain the good GPA, you'll be keeping your options open. If you regardless choose not to, make sure that you have a very good reason that doesn't leave any nagging doubts in your mind. Take the outside view and keep in mind that at 17, it's very unlikely that you'll know yourself well enough to be certain about never changing your mind. You simply haven't been exposed to sufficiently many lifepaths and social/work environments to know which ones you'll actually end up detesting, let alone which ones you find the most comfortable. (I still haven't figured this out for certain at 25, and I would not be surprised if I was still unsure at 40.)
As a continuation of the original Welcome thread (if you haven't gone there, go there fist) I think we need a separate introduction thread for highschoolers.
Who: As a demographic, I think that we can probably be characterized by:
1. Our newness to LW.
2. Our uncertainty about which college or career to choose.
3. (if we are in a public school) Looking for ways to game the system (because we're not learning much in it).
4. Our potential to make a huge impact (the best advantage is an early start).
5. An lack of face to face interaction with intellectual people.
Why: I can think of several things this could help highschoolers with.
1. See where you stack up compared to others your age (We're probably all big fish in small ponds. At least I am. Let's get an idea of what the big pond is like).
2. Make friends with people like you.
3. Consider college and career ideas you hadn't considered before.
4. Perhaps find people to apply with for the Thiel Fellowship.
5. Find a chavruta to go through the sequences with you.
What: Tell us the following:
1. How old/what year are you?
2. How have you tried to enhance your education beyond what's normally offered at schools?
3. How many rationalist/philosophical people are at your school/family?
4. What careers/schools are you considering?
5. Are you going to apply for a Thiel Fellowship?
6. EDIT: link to your old "introduce yourself" post.
If you're not in highschool, tell us what you would have told your old highschool self.