I'm going to tell you a little story: WAAAY back in the day, I was in a similar situation as you. I never told my friend that I liked him, but it was obvious that he was into me (he also treated me differently than other girls). We parted ways when he graduated from HS (he was a few years older than I was). Fast forward 15 years...I run into his best friend at jury duty. We chatted, caught up and I brought up this guy. The best friend tells me that he really liked me, but he thought I didn't like him back so he never said anything!! Argh!!!!
It is one of my biggest "what if's" of my life....so the lesson here is:
DEFINITELY MACK IT!!!!