Looking for a story Again!!

While reading another story, I remembered a story

Ballroom Dance Competition

Protagonist and Antagonist enter the competition, something to do with school

Protagonist's mother is teacher at the same school (teaching under maiden name) maybe sports teacher, can't remember if father is still in the picture or not

Protagonist's mother also runs a dance school

Antagonist only finds out that her Dance teacher and the Protagonists mother are one person until after the competition, and to add insult that to injury that the protagonist has been dancing since she was able to "Walk"