Might as well get used to it, we're all "That Mother". You just need to be honest. Tell them she can read, do simple math etc. Ask them to use the first couple of weeks to kind of get a feel for her. Once they do you can ask them where they're headed, ideas etc to make her pre-k experience great.
In many cases with littles, it's better to let them(the school) discover for themselves where she's at academically. If they are in fact willing to let her work to her own level they will take the time to find out what that level is.
Take a deep breath and jump in!
