I deferred my Summer born son so he started Reception just after turning 5.
We didn’t do it for academic reasons though, only for social/emotional development ones.
In Years 1 and 2 he joined the school year above for maths and English (the cohort he ‘should’ have been in) as he was so academically able but from a social point of point it was very obvious he was a lot younger than the majority of the class.
He’s now in Year 4 and you can tell he’s one of the oldest in the class (to look at) and he’s excelling academically and he’s so confident and outgoing, and although I have no doubts that he would have been academically fine if he was in the school year above I don’t think he’d be as confident or enjoy school as much because I think being the youngest in the class would have had an impact on his confidence levels and friendships etc (which is what our concerns had always been and what we’d wanted to avoid).
He plays football for a team that is the age group above his school year (so the cohort he should have been in) and again, when watching the team at social event it’s very obvious in their behaviour, social skills, resilience, mannerisms etc) that my son is the youngest in the team and he is a little bit sidelined at times. I can’t quite put my finger on the ways it’s obvious he’s younger, but you can just tell. Whereas in his current school cohort of being in the Year below, he fits in perfectly amongst his Peers.
He primarily hangs around with the children who are the oldest in the year so I do think there is a natural gravitation pull that occurs between children who are at the same level of emotional/social development and maturity and I am very glad he’s the oldest in the yesr and not struggling from that angle, as opposed to being the youngest and potentially having difficulties.
When you read all the research although it does talk about the potential academic restrictions of being a Summer born there is also a large focus on the detrimental effect it can cause children by
not being socially and emotionally ready for school at just turned 4 and the impact that can have on their behaviour, their character development and the secondary impact of how that can then influence their academic achievements.
As has been said though, the research also says that boys are much more likely to be affected than girls so your daughter does have that protective factor.
The school have spoken to us SO many times about moving our son up a year to the cohort he ‘should’ be with based on his academic ability but we have always said no, as that was never our primary reason for deferring him.
We have always been very open with our son about the fact he was deferred and he has always been involved in discussions about moving him up a school year but he has never wanted to. If at some point in the future he does want to then we’ll cross that bridge when we come to it.