Curious but which adults? Teachers/Guidance counselor/parents?
Most schools districts have test out options. Teachers unfortunately like to see actual progress not just potential before they recommend advancement/testing out. You have to show them something in the way of results so you need to learn to play the game.
For example, if you feel you know geometry, they should have a test you can take to show proficiency. Back in the day, geometry taught structured logic as well as just how to calculate area, etc. The two subjects of interest could potentially require probability/statistics and higher level physics/chemistry. These can require some amount of calculus. Unfortunately, there is a progression to get to those classes.
Instead of thinking what is wrong with everything, try to find something positive that can make a difference. Ask the district how to test out of subjects. Maybe they have dual enrollment with a jr. college. Take the SATs, get a GED and just go to college? I think it is MIT that has some advanced courses that you can take online (not for credit but for intellectual stimulation). There are many options.
