So my best friend wants to be my gf?

ok, so me and by best friend jodie (im a guy shes a girl) are pretty much like pb & j. Were closer than brother and sister, yeh, best friends is the term alright. So Im 14 and shes 15, were in 8th grade (which is almost over and weve been best friends since the first day of 8th grade) so 5 minutes ago she told me she wants to be more than best friends, she wants me to be her boyfriend and she says she wants to be my girlfriend, im single and all but i really dont like her like that. I love her (not like romantic love but like really close friend love) and i couldnt stand to see her cry if i told her that i didnt like her like that because shes my best friend in the whole wide world and nothing can seperate us. I havent replied to the text and IDK what to say, i dont wana hurt her i really want to keep the really close friendship we have now, and im afraid if i say something other than lets go out then shell cry and not wana see me, like ever again. I dont know what to say to her, what do I say? i couldnt stand it if she started crying because of me, so my big question is, what do i say to her? what do i reply back to her? im so confused