How do I know if my best guy friend likes me or not?

There's this guy I kinda have a crush on. we've been really good friends since the 2nd grade. no were in middle school and we are closer than ever. we sit together in science cl and since we're both really good at science we just talk to each other instead. I know for a fact that in 4th grade he liked me, but i was dating someone already. now that i have the crush i don't know if he feels the same about me now? i asked him once if he liked me, he said no we're just really good friends. but that was last year. but this year. he's purposely trying to make me laugh and smile. he's talking to me about things that he doesn't talk about with his friends. he's being really helpful. he listens to me. and aks like he wants to be more than friends but I'm just not sure if that's what he's feeling? If anyone can help a person in middle school. please help!!!!!!!!!!!!!