Too late to defer, what are our options

[Watermelonsuns]

My son is born in August and was one of the youngest in his class starting school having just turned 4. We had discussed deferring him starting but felt he was ready and excited to go. Fast forward two years and I'm massively regretting it. He is doing ok academically but is already struggling a bit with his reading and concentration. He's got into trouble for not being able to sit and do the work which I feel is partly down to his age. Im also worried about the future and him being forced to grow up too quickly compared to his peers and things like doing his GCSEs when hes nearly a year younger than some of his peers.
DH agrees we probably should have looked into deferring more at the time but that its too late now and we need to make our peace with it
Im really struggling with the guilt of it all and wondering if there is anything we can do? Socially he has a little group of friends however it sounds like he gets bossed about a bit by a few of them and I worry about that too.
Anyone been in this situation and found things got better? Ive spoken to the school but they said to have him held back a year would not be in his best interests and would need to be approved by the board and this has only happened once for a child with SEN.
Really struggling to know what to do here, any advice is appreciated

You could try a Montessori school as they often have more flexibility for children who are a bit behind or a bit ahead.

No help here - same situation and also couldn’t change it at a later stage. Teenager now and it’s really not great being the youngest, smallest, least mature boy in the class. Academically not a major issue although he’d probably sailing through with zero effort if he was a year older

Yes this is what I am worried about, my DS is tall for his age luckily so doesn't stick out as the youngest yet. Im really debating looking at moving schools we are planning to move in the next year or two to a bigger house so would be easier to explain it to him. Just don't know if other schools would be open to accepting him repeating a year essentially at their school

As the parents of teens.. by high school, the Aug borns tend to academically be level. Yes they are young for year but kids also hit puberty & growth at all different points.