Im in vic.
Here the children born up to april 30 can go at 3 turning 4, or 4 turning 5.
My ds turned 5 in march. We sent him to kinder last year at 3, turning 4 in march . We thought he was ready. His childcare educators said he was ready.
But he was not. We made the decision to repeat kinder, so he's now in his second year of "4yo kinder"
Honestly for us and our ds (all children are different) it's been the best decision. He's come so far already. He's handling his emotions better, he's excited about writing and starting and controlling a pen/pencil.
He's so much more out going (he has always been confident but you can really see it now)
At first when his teacher suggested pulling him out of kinder for the year i was offended and upset. So we kept him in...going he would catch up but he didn't so we are repeating and it is best for us