Hi JoJo,
Great News!
Whatever you decide, either way is good. Do either of your girls have much of a chance of 'passing' as older? If not, then call to set up a meeting now.
Our school had an 'open house' the day before school started, so that the kids could learn their way around, and DH took DS, and they chatted informally. It was perfect. BTW - we aren't seeking additional subject acceleration, so we didn't say a thing about the skip to the teachers. I'm sure they won't mention it if we don't so we have no way of knowing if they know. LOL!
Grinity