This is a concern I've been having as well as my son has mid-December birthday. He's just turned three and according to a checklist I was given, he's already mastered most of the kindergarten skills. However, I'm concerned that accelerating him wouldn't be good for him socially. He seems to be an introverted kid and is quite shy around strangers. Polarbear, I note that things turned out fine with your son, despite a late birthday. Does anyone else have experience or advice on this? How wise is it socially to accelerate introverted (and possibly shy) children, despite their intellectual abilities?