you might try talking to a school nurse to see what you can do if your mom won't take you to a doctor. the school nurse probably won't be able to do much directly, but might be able to help you get to the care that you need
I didn't read the whole thread so I dunno if someone has mentioned this, but pilates was actually created by someone with scoliosis specifically to manage it. Perhaps that would help.
Ha! That's interesting - I was getting ready to say "find a kung fu school" because that would be the physical therapy and the medicine, but I really did not know that about pilates.
I'm not saying to straighten the spine fully. I'm saying hold your shoulders back. Even with a kyphosis curve like you describe, the rotation of the shoulders can go back.