Time travel loop? (massive spoilers!)

The movie starts when Seh-hee bumps into crazy looking woman wearing mask on the street, break her picture, takes it to fix it, goes to the coffee shop to meet Ji-Woo, and the story starts. As it progresses we finally learn that the crazy woman with a picture and the mask is in fact Seh-hee after numerous surgeries. So basically, she bumps into herself in the beginning of the movie??? How come no one is discussing it here??