The Wedding Planner's Daughter by Coleen Murtagh Paratore

Twelve-year-old Willa Havisham is a classics reader, a cherry-cordial eater, and quite possibly the world's worst wisher. But when she and her glamorous single mother, Stella, move to Bramble, Cape Cod, Willa's wishes begin to come true: She makes her first-ever best friend, Tina. She bonds with her hip, candy-making Nana. And best of all, steely Stella is falling for Willa's English teacher, Sam -- he's perfect dad material! But before Willa can marry off her mother, or dance with her adorable crush, Joseph, a pit gets stuck in the wishing well.... Can Willa undo the damage before Stella misses her chance to say "I do"?