This is a difficult issue. I've been a teacher for 30 years and most of the time we recommend not to move up or down a grade (repeat). It sounds like academically, your daughter should go to K. She also seems to do well socially, so there shouldn't be any issues. I think the issues that come up in these situations are further in the future. I'm a middle school teacher and there IS a difference when you are 10 in 6th grade and everyone else is 11 and 12. I teach in a school that has a progressive and challenging curriculum, so we meet the needs of a wide range of abilities. I've had some extremely bright kids who did not skip a grade and now are flourishing in HS, with all kinds of advanced classes and activities, college courses, etc. The thing is that your peers and social life are probably the most important thing in grades 5-8. This is just a developmental thing. Even the smartest well adjusted kid often tries to "hide" their giftedness, so as not to appear different. This isn't necessarily good, or the thing that should make your decision, but you could have an ugly 2-4 years just because your daughter is less physically developed and has different interests than the majority of her peers. A good school will deal with this, but it might be good to think of this when you are making your decision.