Now that I think about it more, I might have some insight into this.
I have two kids who graduated from the eighth grade this year. No, they’re not twins — one is 14 and the other 13. The older one was held back by us for a year. Both have birthdays in Sep/Oct.
My son (the 14 year old) was the oldest in his class (as you can imagine). My daughter was one of the youngest. They’ve been that way for the last eight years and will continue that way through high school.
The choice to hold a kid back or not needs to be made taking the kid’s abilities and capabilities into account. Our son, we felt, needed the extra year of pre-school, and so he was held back. That was not the case with our daughter. Both of them do well — I don’t find that my son dominates his class nor do I find that my daughter had difficulty in hers.
Ultimately, each kid is different, and there cannot be a “one size fits all” answer to the question.
The Wolf