Heaven to Betsy/Betsy in Spite of Herself by Maud Hart Lovelace

Heaven to Betsy: Betsy Ray is loving every minute of freshman year at Deep Valley High—with new and old friends all around her . . . not to mention boys! But most intriguing of all is the one she and her best friend, Tacy, dub "the Tall Dark Stranger."

Betsy in Spite of Herself: Betsy is at the center of every activity as a Deep Valley High sophomore—and suddenly, thanks to her old friend Tib, she's offered a golden opportunity for glorious transformation. But will she impress the special boy by becoming dramatic, mysterious Betsye—or would she be better off just being Betsy in spite of herself?