The transformation starts in 1987 in the basement of just-turned-13 Jenna Rink, played by Shana Dowdeswell and later by Garner. Jenna is an awkward girl with braces and wadded up tissue paper for boobs. Her long-time best friend Matt (played by Jack Salvatore Jr. and, when grown, by Mark Ruffalo) has been counseling her to be herself, an original, and not like the school's catty in-crowd of six golden girls. "I don't want to be original," she tells Matt when he first suggests such a lame idea, "I want to be cool." The cool girls, however, treat Jenna like dirt. Enter some magic "Wishing Dust," and Jenna accidentally gets her wish to be just like the women in her favorite magazine article, "Thirty, Flirty and Thriving."

Jenna awakens in a strange bed and with fully grown breasts. She is shocked by her body, but not nearly as shocked as when her boyfriend comes out of the bathroom and exposes his "thingee." "Gross!" she thinks. Jenna finds that it's now 2004, and she's a 30-year-old magazine editor who has achieved great success through some despicable means. She's sadly surprised to find that she dumped Matt like he had leprosy soon after her 13th birthday. He's happily unsuccessful and engaged to be married.

Unlike Jamie Lee Curtis in FREAKY FRIDAY, Garner is more cute than convincing, but who cares. She'll charm the pants off of you. The "new" Jenna wows her office and enlivens a party by getting the audience to dance like Michael Jackson and crew did in his famous "Thriller" music video. Her coworker, Lucy (Judy Greer), was one of the cool girls who used to harass her until Jenna became one of them. Needless to say, Lucy is still evil.

The sweet, good-spirited film is a fun ride, full of good laughs. Parts of the ending are a little dopey, and the movie drags a bit towards the end; but it concludes both predictably and perfectly. As I said, take your kids if you have some, and, if not, go yourself. You'll enjoy it.

13 GOING ON 30 runs 1:40. It is rated PG-13 for "some sexual content and brief drug references" and would be acceptable for kids around 8 and up.