I've JUST found out he KINDA likes me!!I know its long, BUH PLZ?

i was in town today with my friend, and i saw this guy that i really like, and we do talk, (sometimes) i was going to ignore him but he stopped me and went don't you say hi to people, and i just laughed and i went to say hi to him and he asked me what i was doing and i told him i just came to buy my uniforms, and then everything was quite awkward, and he was with his friend and my friend's older brother, and i told my friend to go drop me to the bus stop. and she asked me if i liked him the brother and sister way (coz we act like it, apart from we don't talk sometimes) or more than that, i didnt say anything i just smiled and i said dunno, and she said you should coz he kinda likes you and i asked her how do you know and she went he told me and i didn't believe her so i told her to ask him how feels about me!!but he doesn't know that i like him, but today we're just starring at each other even though i wasn't trying to make eye contact. and what shall i do if he asks me if i like him, but i'm scared coz i don't know what people are going to think coz he's 17 and i've just turned 14(but i look 15), and because his younger sister(she's 16) is like my BESTEST friend, and we're like sisters and i don't think she'll like it if she finds out that i'm going out with him!and i'm afraid it'll ruin our friendship