A Burp With Your Mouth Closed Occassion

I took M to a formal occassion on Saturday night. Mainly because it was my weekend and I had already shipped her off to a babysitter on Friday night, and cowboy and I are somewhat back to our impasse from right before the holidays - do we or don't we meet each other's kids?
In preparation, we went shopping on Thursday and she picked out a brown and blue dress with a brown cardigan (duh, she's my kid - she will have a sense of style). We talked about behavior expectations, and I asked her if she knew how she was expected to behave. She so matter of factly told me, "I know, burp with my mouth shut." OK, I'll take what I can get.
Saturday afternoon she got dressed, put her tights on with her new shoes and looked amazingly grown up. I struggle with this a little bit since if she looks 'older' than she really is at 7, how much older will she look at 13?
Anyway, Saturday night was probably the most grown-up, polite, well behaved I have seen her ever. She got up on the stage to help call the raffle numbers using a microphone. She survived a sit-down 'fancy' three course dinner. And she held it together until after 10pm with no attitude.
Unfortunately, she only has so much capacity to be good for me. Once that good is used up, it's gone. I think for every hour of good, she needs at least two hours of bad to recoup. After four hours of good Saturday night, and a few hours of good this morning, I figure she's in brat mode for me until at least Friday.