Small Medium at Large (Hardcover) by Joanne Levy

After she's hit by lightning at a wedding, twelve-year-old Lilah Bloom develops a new talent: she can hear dead people. Among them, there's her overopinionated Bubby Dora; a prissy fashion designer; and an approval-seeking clown who livens up a séance. With Bubby Dora leading the way, these and other sweetly imperfect ghosts haunt Lilah through seventh grade, and help her face her one big fear: talking to-and possibly going to the seventh-grade dance with-her crush, Andrew Finkel.