It's been 15 years since "13 Going on 30" hit theaters, meaning this rom-com about an awkward teenager morphing into an adult is now old enough to be an awkward teenager itself. Celebrate this anniversary with a few fun facts you might not know about "13 Going on 30."

1. "13 Going On 30" isn't the only time Christa B. Allen has played a younger version of a Jennifer Garner character. She also shared a role with Garner in 2009's "Ghosts of Girlfriends Past."

2.Gwyneth Paltrow, Hilary Swank and Renée Zellweger were all considered for the lead role before Jennifer Garner was cast.

3. Jenna morphs into a 30-year-old woman exactly 13 minutes into the film.

4. Both Jenna and Lucy's wardrobes evolve as the character's respective personalities change. That's why Jenna wears progressively warmer colors over the course of the movie.

5. On the DVD director's commentary, Gary Winick notes that he originally clashed with the studio over their insistence on including the slumber party scene. In hindsight, Winick considers it to be one of the best scenes in the movie.

6. Jenna's birth date is shown to be May 26, 1974, making her about two years younger than Garner herself.

7. The scene where Jenna first sees her adult self in the mirror was framed as an intentional homage to 1988's "Big," which features a similar premise.

8. Choreographer Michael Peters is included in the credits despite Peters having died in 1994. That's because Peters performed the choreography for the "Thriller" music video, which is replicated in one of the most memorable scenes in "13 Going On 30."

9. Future Oscar winner Brie Larson made her film debut here as one of the "Six Chicks." Her character is the one who is replaced by Jenna in the altered yearbook photo.

10. The scene in which Jenna confronts Matt before his wedding features a copy of Martin Amis' "Time's Arrow" on a shelf. This is appropriate, as "Time's Arrow" is about a man experiencing his life in reverse order.

11. The train scene was filmed on the exact same train Winick previously used in 2000's "Tadpole."

12. The movie's title was changed to "Suddenly 30" in Australia, as executives feared the original title would be too confusing.