I read this short story in the early 90s and I would love to get hold of the whole book. I think it was an anthology of female science fiction and fantasy writers, possibly lesbian writers.
The story I remember best is a retelling of Cinderella from the godmother's point of view. It becomes clear during the story that the godmother is a vampire and that she has chosen Cinderella to join her. Cinderella is excited about getting beautiful dresses and going to balls and doesn’t understand the transformation that is happening.
The godmother character lives with the family during this time and it’s obvious they know what is happening but they are poor and accept it as ultimately being in Cinderella’s best interests. The pair go to the ball and it’s only when the godmother makes a comment about needing the invitation to be able to cross the threshold that you realise as a reader they are vampires.
There is someone at the ball that tries to kill them and that’s all I remember.