I am doing the local equivalent with ds4 if I can. We start school whenever in the year our birthday falls but there are cutoffs for whether you go straight into year 1 (K) or finish the year in year 0 (a bit like preK though they do exactly the same stuff just have more time).

Ds6 made the local cut off by 2 days which was fine but ds4 misses by just over a month. So far they are willing to put him in the year one class (there are usually a couple who just missed the cut off in the class to make up numbers anyway but he was supposed to go in an entirely year 0 class) and assess at the end of the year. Ds4 unlike ds6 is little but i think it would probably be easier to get him put ina lower level for sports than to get his academic needs met in a lower class.