I've never heard of IB classes, but like Golden said, at my school we have AP (Advanced Placement) classes. They are very challenging courses. I have AP English right now, and it is quite a difficult class. I'm praying for a 3 on the final test in May, because the highest score you can receive is a 5, and that's just not going to happen here! LoL I did not have to take a test to take the class, but I did have to sign a form before the first day of school this year saying that if I agreed to take the class, I couldn't drop it even if it was too hard. Believe me, there have been many days I've wanted to quit, but I'm hanging in there! It sounds like the same thing (almost) happening at your school. I would suggest talking to your guidance counselor at the high school. They will be able to help you out! Good luck!