I'm not sure how helpful this would be but my brother repeated prep approx 25 years ago. He was a handful bubba right from the start and never settled into his first year of school. I'm not too sure of what else was behind it academically/social-emotional or how he feels it effected him or if he even remembers doing it.

But on the other hand I repeated in grade 3 (I was an April baby and turned 5 the year I started school) I tended to struggle all the way and i'm sure it was the right decision for me but it was a lot to deal with socially and emotionally. I don't think it was the wrong decision but i wish it didn't have to happen.

For these reasons and more specific reasons to my children i have held all 3 of mine back to start kinder later rather than earlier.

I also have a SIL & BIL struggling with this right now. Their situation is a little more complicated as it involves moving interstate and then moving back again and trying to find where their son best fits in. It looks as though he may be repeating yr 3, at any age this is a difficult decision, my nephew is a couple of weeks off turning 10 so similar age to me and i really feel for him and his parents in trying to figure out what is best for him.

I realise that these examples don't relate a whole lot to your situation but as has been said and i passionately agree if it's necessary do it sooner rather than later.

Big hugs and good luck in making a decision.