13 Going On 30 is a delightful be-careful-what-you-wish-for romantic comedy starring Jennifer Garner and Mark Ruffalo. On the eve of her 13th birthday, all Jenna Rink wants is to be pretty and popular. After a humiliating experience with the coolest boy in school, Jenna makes a desperate wish for a new life. Miraculously, her wish comes true, but with one catch... it's 17 years later and she's a 13-year-old trapped inside her 30-year-old body.