K.H.
I am in slightly the same situation. My daughters are 2 years apart, but where the birthdates fall, the youngest wont start kindergarten for 3 years after my oldest. Like you, I wish it wasn't that way. I would have liked that they would be closer in age (by that, meaning grades as well). I do think that it will distance them from one another moreso than if they didn't have that extra year in school to seperate them. I also feel bad for my youngest, as she will turn 5 right after the cut off date...which will kind of make her one of the older ones of the class once she starts. I feel like she is going to be ready to start long before they let her.
K.