Grrr Im so confused :S Can anyone give me good relationship advice?

Alright so im a guy in highschool, moderately good looking at least, and I have as many friends that're girls as I do that're guys. I don't flirt with my friends but still....some of them end up falling for me but..the thing is, is that I don't want to go out with them bc 1. I've known them for too long 2. I don't want it to effect our friendship and 3. I wanna go out with a girl I don't really know that well first before I screw up my friend's life... is that reasonable? what am I supposed to do if my friends like me? and what am I supposed to do if I like them back but know I shouldn't go out with them??....I'm so confused right now.....help?