Sondia's "First Love" (첫사랑) is a melancholic ballad from the Extraordinary You (Part 3) OST, famously known for its poignant lyrics about the fluttering emotions of a first love. You can find the full lyrics, including Romanized and English versions, at these links: Genius AZLyrics Bugs 어쩌다 발견한 하루 OST Part.3 듣기 및 가사