Go 3yeogyosaeng(2016)

Go 3yeogyosaeng

MC tries to buy some alcohol but gets mistaken as a minor by the male lead because of the way she's dressed. She is unable to provide verification of her age as she left her ID at home, furthering the misunderstanding that she's younger.

They meet again at school and it turns out that he's a student at the school where she will be teaching. Although she's already late to work, he gets in her way. When asked why she wasn't wearing a uniform, she lies and says she's a transfer student instead of telling him the truth like a normal person. After getting attracted to him, she now uses that lie to disguise as a high schooler so that she can meet him.