Okay now hear me out....

I like this boy who is 3 years older than me and is my brothers friend, I’ve liked him since I was in 6th grade (I just graduated high school) and I can’t get him out of my mind. He currently has a girlfriend so of course I’m not gonna make a move but he’s so freaking hot and every time I see him my heart literally beats so hard.... I just wanna get closer to him but he still sees me as his friends little sister, I wanna be seen as one of his friends I just don’t know how to go about it bc I’m a really shy and socially awkward person , sooooooo do any of you know a way that I could get closer to him without crossing the relationship boundary bc I really need the help