She was 23 years old and you were 19, but age didn't matter. He had invited Yunjin to a party just like you so they went together, she was very jealous of you, since she always said that you were hers and no one else's. You were talking very peacefully with some people who were acquaintances of yours who ran into each other at the party, ha, of course, Yunjin didn't like that AT ALL, especially without even asking his permission...