Gayoung is usually a very nice and cheerful spirit, always trying to cheer people up if they're down. mainly the mood setter of the group, she takes her position as the bright one very seriously. careless, fiery and blunt at times, Gayoung uses her charasmatic and captivating personality to hide how anxious and clumsy she truly is. fanciful, aspiring and determined, she is sure to achieve her dreams and capture the hearts of people everywhere whilst reaching for the stars. although childish and gullible, she is also known for her brillant way of thinking and her bright smile.

Gayoung was born on November 2nd, 1999, to her mother Seo Jinyuk and her father Seo Minkki. She was a very bright and passionate child, getting into music at a young age when her mother first introduced her to Korean Pop at the age of six. After that, Gayoung was obssessed and wanted to be put into singing and dancing classes and her mother being the supportive woman she was allowed it after speaking to her husband. Gayoung did fairly well for a six year old in classes for dancing and singing, quickly picking up her skills as she grew. Her classes continued on till third grade at the age of nine when she heard EMPIRE ENT. would be holding trainee auditions and begged her parents to let her audition for a spot as a trainee, her parents having a very long discussion until it ultimately led up to them agreeing because they wanted their daughter to be happy and live out her dreams hopefully. After hesitance and mustering up the courage to send in her audition tape, Gayoung waited a few weeks till they got back to her with the surprising news that she'd been accepted as a trainee. From then on, Gayoung's life and schedule had gotten hectic and she barely had enough time to keep friendships going at school so she decided she'd try to be friendly with the other trainee's there. Her training proved very difficult though, and despite Gayoung having a great amount of control over her vocals, she had trouble with working with the others and that made her mess up a lot. After a long period of training time, she was able to work well with the others, her whistle notes were impecable and her body movements when dancing were fluid like water. Her schedule though became less hectic when she decided to school in the training room with a tutor, having more time for training, telling her parents that if her dream didn't take off she'd end up going back to highschool instead, though she was pleasantly surprised when there were rumors of trainees being picked to be in a new debuting co-ed group and this drove her to work even harder, determined to get a spot in that group.