I don't know which is worse, but in our experience with DD6, being in a kindergarten class with age peers and being pulled out for reading and math to do with the 1st graders was not a good social move. It wasn't so much because she was singled out as the smart one, but more that she seemed to get the feeling that she didn't really fit into either class. Since we've moved her up to gr 1 fulltime, she is much happier socially, even though she is still not quite with her intellectual peers, they are at least closer. (In Colorado you must be 5 by July 1st of the year you are to start kindergarten, and our district does not allow for early entrance, that's why she started the year in kinder and not 1st).
