I'll add another perspective; we've chosen not to skip our son, also born in the fall, 10 weeks after the cutoff. At our school, it is common for summer born kids to be held back, so our son has about 5 kids (in his class of 20) older than him. Our son is very far ahead (reading third grade chapter books in preK for example), but he is very, very happy.
The issues to consider are social/maturity and fine motor. Socially, it's about more than a good fit with peers; it's also about classroom expectations for attention and behavior. Is she ready to sit and learn more than play? My son would really miss the playing at his current age.
For fine motor, this was a big concern for us because his preK class is expected to write sentences (not copy but spell and write). K expectations here are a full page of writing on the lines. Our boy was just not ready for that.
I just want to encourage you that the decision you make now doesn't determine her entire future. My DH was grade-skipped as a child and then moved to a school where he didn't speak the language at age 7. They moved him down two grades to K for three months then moved him back up one grade to 1st with his age mates when he spoke the language. He went to a new school two years later and was skipped back to a year ahead. He went on to graduate as valedictorian a month after turning 17. No need to feel that the decision you make now can't be changed or undone in the future!
