Most Helpful Guy
aha god sister zoned that's a new one, trust me 'sister zone' is a lot easier to get out of than when a girl basically friends zone a guy because they're not interested. Unless the guy doesn't find you attractive one bit he might simply just not know you're attracted to him.
I think the best solution in this case is if he's actually single and not dating anybody is opening up to him and let him know, you're under 18 so trying to explain to a teenager guy that you like him with clues and special wording isn't normally going to work, you need to be blunt and honest. Normally and the likely case is he just doesn't know you like him and so he's keeping you around as a 'sister type' kinda girl until he can actually figure that out. So if you open up and just even just ask him if he wants to go on a date together simple as that. If he's not attracted to you than he values your friendship and he won't go around being a dick about it or anything or ruin your friendship so you might as well ask.
Most Helpful Girl
He is not into you no :(