It sounds like she is trying out her socialization skills and trying to figure out what works in your social circles. In this house, we compliment effort and we highly compliment practice. When my husband or I make a mistake, we smile and say we just need more practice. For a kid who almost always gets things on the first try, it is nice to emphasize practice as a way to get even better. Even professional athletes practice... We emphasize that especially professionals practice...
People often criticize themselves to fish for complements. Does she see this modeled by anyone? If I were in your shoes and she criticized something she did, I would probably tell her that I think it is wonderful but that if she is unhappy with it that with practice, it will get even better.
