How to ask a guy out???Please help!!!?

sooo i really really really like this guy(he gives me goosebumps and all that) but i am only 13 and he is 14 and i have no idea how to ask him out or what to say or do if he says yes or no because i would risk our friendshio to ask him out but would still be devistaded if he said no (aquward) so how do i do this???? I am so terrified!!(btw since its summer i wont see him at all unless we make plans so all i hav is my phone and facebook)