Hi OP, I know how you feel I have 2 winter babies and then the 3rd is a July birthday. I had an interesting piece in a book (Freakonomics? Or one on the Malcolm Gladwell ones?) about the disadvantages of being born at the end of the school year. Not just in academics, but as a previous poster said, in sports. There had been some study of something like an ice hockey team in Canada, and most of the top athletes were born Sept- December.
But, but, but... there are always outliers.
DC3 seemed very young in Reception: she was just 4, and a lot of the very articulate, able girls are September and October birthdays. She was hitting all her targets, but I’d say not as socially mature, and just exhausted by the school day. Her sister had always wanted play dates, dc3 just wanted to come home and watch peppa pig.
Nearly 4 years later, she’s on the ‘top’ table at her local primary (her words, not mine), and working above the expected standard for maths and writing, and expected standard for reading. She still seems ‘young’ compared to a few of the girls in her class, but she’s fine.
I have not spent as much time on reading/ workbooks etc as I did with my first born (eek!), probably because due to the age gaps, I was working on 11+ stuff for her older siblings, and I was sooooooooooooo over Kipper, Chip and Biff
Your DC is going to be fine, just on the back of having an interested parent who cares enough to do some research, and ask for advice on mumsnet.
I work in a primary with a very challenging intake, and lots of children turn up having had no breakfast, smelling of weed, in dirty clothes - this sadly will play a much more significant part of their development that their birthday. :(