Gary Winick’s romantic comedy about an awkward teen who magically fast-forwards to adulthood retreads a well-worn premise (Freaky Friday, Big) but the formula works, thanks in large part to star Jennifer Garner, who’s so radiant theaters should be stocking sunblock. The rest of the cast also pull their weight: Andy Serkis channels Tony Randall as the mature Garner’s boss; Mark Ruffalo plays her nerdy childhood friend, who’s grown up to be a hunk; Judy Greer is her teenage rival, who remains a bitch. Underlying the shenanigans and the pop-psychology moral—self-love is a prerequisite for true love—there’s a touching wistfulness about roads not taken. PG-13, 97 min.