YA Unconventional Mother

Hi all! Read this book sometime around 2005-2009, but probably on the earlier end. It was middle-grade/YA at the oldest. The protagonist is a girl, who has a very eccentric mother. They drive a hearse, and her mom teaches her friends (swim team??? classmates?) about kegels to her daughter's horror. She grows to embrace not being normal. I remembered it being fairly lighthearted.