For my PG DD, who entered K at 4, discovering that a good half her classmates were entering K at 6 worked in her favor-it meant at least a couple of other kids could read and therefore the teacher was used to having them do AR and read independently instead of doing the boring phonics lessons. She was STILL the most advanced in the room, but she at least wasn't the only one who had her own packet of math pages and her own book in her chair pocket.
I will say, though-the fact that she was 2 years younger than most of her classmates (she'd been early entered and was only born 8 weeks before the cutoff date) did play into deciding to homeschool-because PE and the playground were total nightmares for her. She was just plain too little and too young motor-skills wise to keep up, and the PE teacher had the attitude that she should just be able to keep up with 6.5 to 7 yr olds as an older 4/young 5 yr old. DD spent a lot of PE classes in tears, furthering the PE teacher's perception that she should never have been allowed to enter early in the first place.
I also noticed, when DD did the EXPLORE last year, just how BIG the kids were. She was taking it at 3rd, in a Duke TIPS area where almost no 3rd graders take it, and was a young for grade 3rd grader, and in talking to the parents, a lot of these "gifted" kids were a year older than expected for their grade.
She still scored very, very high compared to 3rd graders-or 8th graders, for that matter.
