Is 13 Going On 30 just a female version of Big? Well, yes and no. In both movies, the protagonists find their young ages inadequate for their desires, wish to be older, and wake up as adults the next morning. There is a major difference, though -- in Big, the main character becomes instantly older overnight, literally. When the main character in 13 Going On 30 awakes, she not only finds herself older but also living in the future. She's lived 17 years of her life, but the last thing she remembers is her thirteenth birthday, the day she made the wish.

There's actually another important difference, one less detectable from the surface of the premise. Big was primarily a story about learning the value of not growing up too fast. It projected a warmth that spoke to the child in each of us, and thus had the bittersweet touch of a gentle fable. 13 Going On 30 isn't quite as daring. It's primarily a romantic comedy. The antics of Jenna Rink (Jennifer Garner) are constructed to show her the path to true love. The film isn't about growing up as much as it is about finding out Mr. Right was your best friend all along.

If I'm making the movie sound shallow and formulaic, it's mostly true although not entirely fair -- there are edges to the story that give it a little something more, and those can be appreciated. What Jenna finds out is that an early decision to join the "cool" crowd at school ultimately leads her to a life of shallowness. By having the results of the shallowness thrown right before her, as opposed to having her achieve them gradually, she's able to realize them for what they are. I suppose this lesson could be applied to the lives of real people who have gone down regretful paths before realizing how much they've completely changed, but, frankly, the story is handled in too lightweight and silly a fashion for that thought to carry much resonance. Still, it's there, and it's interesting.

However, I found a different bit of "commentary" more interesting. Jenna was a child of the '80s, and she grows up to find herself in 2004. The movie includes many moments where Jenna perpetuates the colors and energy of the '80s, almost as a direct slam of the ambiguous cultural sludge we're living in today. Stuck at a company party where the music plays a dreadfully thudding, generic dance beat, and having observed the guests getting bored and leaving, Jenna insists the DJ play Michael Jackson's "Thriller," to which she leads a rather hilarious dance number. Soon, everyone joins in. Again, it's rather silly, but it has an interesting point, and it's another brick in the house of today's nostalgic mythification of the '80s.

So it's a shame this movie degenerates rather quickly into a cliche romantic comedy climax. Inevitably, the short-lived thrill of being an adult must give way to its unsavoriness, which in this movie ironically comes from high school-level backstabbing, thereby diminishing the depths of any reasons Jenna has for wanting to go back to her old self. By the end, she's primarily motivated by love, and so we get the standard realization-leading-to-mad-dash-before-guy-gets-married scene, and that's where my mind wanders and wonders how many more times this stale device will get used.

What I haven't mentioned up to this point is Jennifer Garner's performance, which may end up being the nudge that convinces people to see the movie. In and of itself, 13 Going On 30 is a poor woman's Big, with not much new to chew on, therefore making it a passable distraction. But Garner makes the most of her chance to shine here -- given a star vehicle at last, she does a 180-degree turn from her Alias persona (and, while we're at it, her Elektra character from Daredevil) and spins gold from it. Garner is adorable playing a bubblegum 13-year-old; she's cute without overdoing it (and this opinion is coming from someone who didn't really understand her appeal before). Her leading man, Mark Ruffalo, is also charming opposite her, and it's their sweetness that gives this otherwise ho-hum flick any distinction.

(Released by Columbia Pictures and rated "PG-13" for some sexual content and brief drug references.)

Review also posted at www.windowtothemovies.com.