Fan Casting Laggies(2004)

When 28-year-old Megan attends her 10-year high-school reunion, she realizes that very little in her life has changed. An unexpected marriage proposal from her boyfriend sparks a panic in Megan, causing her to wander off into the night. She meets 16-year-old Annika who is with friends and proceeds to get drunk with the teens. Deciding she needs a break from her unfulfilling life, she tells her boyfriend she's going to a seminar but hangs with Annika.