Ds was one of the youngest in his year- already reading and writing in sentences when he started school. By year 6 was one of the tallest boys.
A friend at school was born on September 1st, if she had been born a couple of hours earlier she would have been the youngest. Out of 4 sets, with 1 being top, she was in 3 for everything.
A boy at ds’s primary started school a year later, was a lot bigger than the other children in reception and made a big deal about being ‘the oldest, and the biggest’, it all back fired when children started calling him names, things like thick, (and other names that made me think it was the parents this was coming from) because he was in a class below where he should be.
Someone has mentioned sport:- A girl that started later in a relatives primary school, was upset that she was unable to play in the same football team as the rest of the girls in her class because she was a year older, and couldn’t understand why. It was a new team, so all the girls wanted to do it, and she was the odd one out.
I have heard from teacher friends of 3 children who had to skip year 7, and go straight to year 8, as the LEA/School wouldn’t allow it (I don’t know if this is the norm?) and they had to go into their correct year group. It really messed them up, as they had missed a year of work that others had done. They all ended up in low sets, and the best GCSE grades was from one child with 1 C, 5 D’s. My friend said, if they had completed that year, they could have done well. They just couldn’t do the school work whilst trying to do what they missed. Languages,Maths, Science and English were the ones they struggled with the most, as they went from year 6 to year 8.
These are the only few examples I’ve heard since I left teaching, and I knew of none that had done it then, I do believe though that it can be very beneficial for some children. I’ve taught reception class where I’ve had a few children who struggled to go to the toilet alone (couldn’t wipe themselves, do their clothes up after, or would wee/poo over their skirt, dress or trousers), would fall asleep in the afternoon during carpet time, struggled with holding a pencil, very short attention span, struggled with speaking clearly (no speech problems just because they were young), and struggled greatly with reading, writing, and numeracy. So 🤷🏻♀️You do what you think will benefit your child the most. All I would say is think long and hard, if there is a possibility they will have to skip a year.