If both your parents were carriers which I assume they were since your brothers had the disease then I believe there is a 25% chance that you are not a carrier. There is a 75% chance that you are a carrier. 

I don’t know if that would exclude you from egg donation, though. I wanted to donate eggs several years ago and wasn’t able to because I have a genetic blood mutaton called Factor V Leiden. The hormones I would have had to take would give me a high risk of blood clot. I am not sure how they deal with something like CAH.

Sorry I can’t be more helpful.

Eden