Guy I've known for my whole life?

I don't know what's going on. I think I like my best friend that I've known my whole life. And I think he like me but I'm not sure. When ever we see each other we pick on each other and he just make me smile, like all the time. All of our friends think that were gonna end up together, and my sisters think that to. Whenever I'm about to break Into tears I just wanna talk to someone (aka him). I don't know anything right now.