Project Makeover (2007)

Na Jung-ju is a 30 year-old woman whose life is going nowhere, and she blames her misery on a failed high school romance with Jo Ha-ni, who has since become a famous singer. Her old schoolfriend Oh Tae-hun, who used to have a big crush on her, is now a successful and wealthy businessman, and she regrets not having gone out with him. After being given the chance to travel back in time, Jung-ju goes back to 1994 where she tries to convince her younger self to date the future businessman.