Mistaken || Mingyu Seventeen

Kang A Young and Kim Mingyu are friend since 3.Their parent are best friend,thats why they become best friend. When A young had 15 years A Young's parent die in a car crash.Which since then A Young lived with Mingyu.They both are in the last months of 12th grade,ready to graduate.They both think they are just friends, just friends.But when An So Ra, a junior,starts to be with Mingyu al time. Kang A Young starts to feel sad and jealous.
Which both of them start to fall in love? or just end their relation being friends.