I would worry that keeping the 2E info from your dd would be harmful because she surely knows she is different somehow and she is probably working much harder than anyone realizes just to appear average. This alone could lead to major depression: "life is so hard and it's just going to keep getting harder, what's the point?"
A lot probably depends on your school and your child. My experience was that my DD sailed through 6th grade (with math acceleration and Orchestra instead of reading due to testing out). In 7th grade she hit a wall and her grades just went from straight A's to totally random. My DD stayed in the most advanced classes available and aced all of the tests and quizzes in those classes but she just didn't have the organizational/time management skills (EFs) to handle all of the assignments and deadlines.
We discussed putting her in the regular classes since they were less demanding (at that time we didn't know about the ADD) and she was horrified, she explained that she was passing the advanced classes because she already knew most of what was being taught, so the regular classes would have been even more boring. Her biggest objection though was that the other kids in the regular classes were...well... I don't know how to put it politely, but basically there was no potential for finding anything in common with those kids. She was pretty peerless in the advanced classes already, she would have been even more lonely and depressed in the average classes.
My DD already knew she was gifted because every time we moved to a new school district, her teacher would recommend her for the GT program within a week. I think knowing she was smart but her grades not living up to expectations was frustrating for everyone and having teachers questioning her work ethic and calling her lazy was demoralizing. Once we found out about the ADD, it was so good for her sanity (and ours) to finally know what was going on. She knew that she was the smartest one in the class but she didn't know why it was so much harder for her to just remember to do the work and turn it in.
Sorry for going on...
