Don't worry about the other child and having to explain anything to the other parent. DC left her best friend behind as well as all her classmates and it hasn't been an issue at all. They still see each other at school and still can interact, so it is fine. If they wouldn't be in the same class if there is more than one teacher per grade, just explain that part to your child. As far as the other mother, you don't owe any explanations. If she asks, just say, it was a mutual decision with the school. my DC was the first child ever to be skipped at our school and believe me, it raised a LOT of questions, but it's mostly old news now. I still get some questions, but mostly that of shock that they had no clue DC was any younger etc.
