Acceleration has to be taken on a child by child basis. I agree with whoever told you to use the IAS manual in helping with the decision.
As far as the social part of it goes.... For most of these kids, the preference is toward older kids. They have nothing in common with their agemates and tend to find friends that are a few years older. In many ways, acceleration is much harder on the parents who are looking forward to macaroni pictures and kindergarten musicals.
I have DS6 currently powering through Greek Mythology and Pre-Algebra. For him this is "normal". I think that's the most important thing to think about. Define "normal" for your child. It doesn't make any sense for a child to go to school and not learn anything. While I sometimes think about how much easier life would be if my son followed the middle of the curve, I also would never have had the opportunity for 1001 other things that he's managed to surprise me with. Around here, "AHA" moments happen almost daily. It's an awesome thing to watch.
I can't fathom what my DS would be like if he were stuck in a 1st grade classroom all day. Have you asked your DD what she thinks? Willing to bet she'll have an answer...LOL
