I have to agree with crisc that it takes until about 8-9 for the differences to become less noticeable. For my boys, now 18&20, this was the case. They were and still are
"gifted", but it was definitely less noticeable as the other kids started reading, etc. My daughter doesn't stick out (She wouldn't like to) because she's been double grade accelerated. She fits in so well socially and academically I don't think the other kids (outside of her class) even know she's only six.

Laura