At such a school shouldn’t your GC be well informed about good options for you?
Someone once said “Whether you think you can, or you think you can’t–you’re right.” and I think there’s a lot of truth in that. What you are saying is part of what’s called the “fixed mindset” studied by Dweck at Stanford. See, for example, https://www.ted.com/talks/carol_dweck_the_power_of_believing_that_you_can_improve?language=en
Exhorting you to change your beliefs isn’t going to work, I know. Your parents have tried and failed, there’s no reason for you to believe a complete stranger posting here. The only person that can change your mind is you after you look at the evidence, assuming you believe it.
However should you someday decide that people can achieve more if they’re willing to work for it, there are a number of resources you can turn to that explain what to do. One book I’d recommend is the recent book “Make It Stick: The Science of Successful Learning” which is written by some of the leading researchers in the field but with the help of a 3rd author wrote a book that is both informative and practical. And at that “very well known public high school” I think you’ll find that teachers are very receptive to helping kids who decide they want to step up their game.