I am going to use American school system.

Lee Sung Yeol: he is 17 years old, he is in 11th grade, he is rich but doesn't like to brag about it. He is nice to people, and loves to he help others. His parents accepted him when he came out. Came back from Los Angeles California to South Korea.He meets his childhood friend Gongchan again at Woollim HIgh. ( Sungyeol will be shorter and the same age as Myungsoo, I think he will look adorable, he is cute now but I just wanted to make him shorter 

Myungsoo: 17 years old he is a spoilt rich guy,is in 11th grade, he is biual, his parents accepted him when he came out but they really don't spend time together, since he was a little kid. He doesn't help anyone. He is mean and looks cold. Guys and Girls would kill to go out with him. He develops strong feeling for Sungyeol but doesn't want to ask him out because he doesn't wants to loose his reputation of a playboy/ cool guy. He easily gets jealous of whoever talks, or touches Sungyeol (He doesn't realy knows that he likes or he doesn't want to admit it) He is possesive and gets jealous easily. He has 5 friends all guys and they call their group Infinite

Woohyun: he is 17 years old,he is in 11th grade he is nice to people, he is gay, he loves to help others, and he develops feelings for Sungyeol.But doesn't want to tell him because he knows Myunsoo likes him too and doesn't want to ruin their friendship. He is sad and wants to date Sungyeol but doesn't know what to do. He tries to forget about his feeling, so he can just like him as a friend but it's hard, then he starts liking Kim Sung Kyu.

Kim Sung kyu: he is gay, 17 years old,he is in 11th grade his mom accepted him, but his dad didn't, his mom married again and his step dad did accepted him. He is quiet, and nice to people, doesn't like to brag about money. He likes Woohyun but doesn't want to ruin their friendship, and because Woohyun likes Sungyeol. So he tries to forget about his feeling with what he likes the most which is music. And something that happens to Sung Kyu will bring Woohyun closer to him and they will start a relation ship.

Lee Sung Jong: 16 years old, he is in 10th grade develops feelings for Sungyeol but tries to control them. He gets sad but accepts it and tries to move on. He looks and is femine, girls and guys think he is cute, pretty and hot. He also loves to help people, he is also a fashionista. Loves to dance to girl group dances.

Hoya: is 17 years old, is in 11th grade he is nice to people, loves to rap,sing and dance. He is dating Dongwoo.

Dongwoo: 17 years old, 11th grade, is dating Hoya, and is also nice and loves to rap, sing, and dance.