Mag, I just wanted to throw out there that my DD8 was a very shy, quiet child who never wanted to volunteer answers in class and who was often so quiet in class that the teachers told me they couldn't hear her voice. She had plenty of great friends and seemed quite social, but in the classroom she was just so quiet and didn't like to stand out. Still, despite early entrance to K, by 1st grade we found that her academic situation was inadequate. So, in 2nd grade she started going to 3rd grade in the morning for reading and math (and because of the schedule, for p.e. and art as well) and she started to get slightly more challenging work. She wasn't used to challenge at all, and even though the work was rarely difficult for her, the slightest tinge of challenge upset her. But, the challenge was truly so slight and few-and-far-between, that she was able to gradually learn to deal. The other benefit was that she was able to get to know the 3rd graders. But, the biggest change we've seen came this year when she was whole grade accelerated into 4th: she has really come out of her shell! She now raises her hand in class to answer questions, she volunteers to be the class leader, she talks with the other kids, she'll ask the teacher for help, and she is so much less shy in virtually every situation. I truly think the change came about because now she is so much less different than her classmates, most of whom are 1.5 to 2 years older than her. And, while the work is generally still not challenging for her, it is occasionally, and it is mostly new to her.
Anyway, I don't know how much this applies to your situation, but I wanted to let you know that the right academic situation can really help a child to feel more comfortable with themselves. HTH!