Sound advice from others as to passing the buck off on the school if you can. We've used that with some success. And it should become of of a non-issue as time goes on and the skip disappears into the fog of the past.
Our general rule with our DD14 is - don't brag about it, but you don't have to hide it either. In other words, try not to bring it up for no reason, but if it comes up don't be ashamed/embarrassed.
It does comes up occasionally, like during the presidential fitness tests (PE) when the teacher doesn't give out the fitness targets for a young enough age group, but for the most part her age is not much of an issue any more. When it does come up, teachers are usually a little stunned because she fits in so well with her grade peers and her classmates shrug it off because they've known about it now for years.
Best of luck,
--S.F.
