How do i know if this guy likes me?

We go to different schools now but last year there were rumors that he really liked me. I haven't seen him that much this year but whenever i do it always seems like he's flirting..he always teases me and tells me that i'm annoying and finds a way to touch me or smile at me. He is a year younger than me and i don't want to seem like a cougar or anything but i really like him!