Help me I think I'm falling....for my best friend.?

There's this guy I've been great friends with since like the 5th grade. The perfect twosome. Two bffs for life! I'm in 8th grade now and he's not necessarily the hottest guy ever but he's funny and always makes me laugh and he's probably one of the nicest guys I know. He can make anything funnier than it actually is. Once in 5th grade he made me laugh so hard over a stupid koala in this educational magazine our cl wuz reading that my teacher had to send me into the hall to calm myself down. Omg I wuz so embarred and I felt like a total idiot cuz the clroom wus so quiet and he whispered some crack about this koala and here I am sittin there laughin uncontrollably. Sorry I'm getting blabby. :D Well I'm really starting to like him. I'm kind of shy so asking him out is totally impossible for me. And even if I could ask him out would I want to ruin our friendship if we break up? I don't know what to do.