BOY ADVICE PLEASE!! :(?

Okay. So my moms bestfriend has a son a year older then me. My mom and her friend always talk about me and him getting married and stuff. This boy definately isn't bad looking but when i'm not with him i'm just in love with him? But when I'm with him (my bestfriend is his sister) I don't like him! And oh yeah, this boy is in love with me. I don't know what to do! I know I like him deep down BUT I JUST CANT MAKE UP MY MIND! DO I LIKE HIM OR NOT!?