I do suspect that there is an emphasis on pushing little children harder academically now than there was in the past. They were still doing half-day kindergarten when I was five, and the majority of the curriculum was "don't bite the other kids and play nicely." The height of first-grade was basic phonics, single digit addition and subtraction, and coloring between the lines.

On that note, my little brother repeated a year for academic reasons, but it also had benefits on sports. He's older than nearly anyone else in his grade (12th), and he's just about the best swimmer in the state.

I only see positive benefits from his repeating a grade.

I don't think it indicates that students start too young, as much as 1 year increments is too granular for grouping young children.

This. My older kids have birthdays later in the academic year but have ended up in groups for more advanced students.

Mind, nursery was a complete wash when it came to academics -- learning to count to 3 when you can already count to 20 is rather futile. Public schools just can't tailor to individual students.

Socially though, nursery was well timed for them IMO.

That's a good point yeah. But I think when I said that younger kids didn't do as well it meant both in terms of ranking (they were in the lowest percentiles) which indicates that they don't do as well as their peer, but also in terms of future opportunities to attend college or university.