Should i pour my heart out or wait a little?.?

Ok, so im 14 and recently had attractions to my best guy friend. Im pretty sure he likes me too, he always compliments me and says im pretty&perfect and everything. So ive been thinking. And im about to call him up on the phone and just pour my heart out to him right now. the only thing is that im worried that he gets freaked out about how strong my feelings are. so idk what i want to do. idk weather to tell him- or wait a little until i know for sure that he likes me back?. hes pretty mature too. like hes not one of the boys that are like dirty minded or hide their every emotion. hes usually pretty good with stuff like this so idk.