That's a tough one. I will start out with being upfront that I have two children, girls though, with bds around that time or a month later who I did start in K right when they were turning five. We didn't have any fine motor concerns, though, either.
I do wonder if his stubbornness might be more related to giftedness than immaturity. Do you have any reason to believe that he might be *more* gifted than the typical kid in his school? Also, do you plan to keep him in this private school all the way through elementary? If not, I would take a look at how well the school you would likely later send him to would do in terms of differentiation if he was both one of the oldest and much brighter than the other kids in his grade.
Is there any possibility of putting him with the 3/4 class this year and seeing how it goes with the option to skip the 4/5 pre-K to enter K "on time" if his social maturity and motor skills catch up this year?
