You're 19. You're normal. I know very few 19 year olds that are any more clear on this topic than you are. Most are just frightened to say they are frightened. Gay, straight, and bi aren't categories that you have to choose, their just ways of helping you understand yourself. There are some really good threads on this subject around here, but I think you're putting too much pressure on yourself too fast.

Rob's excellent advice to discretely experiment seems very sensible. If your town is too small, perhaps you can plan an excursion to a little more discreet place in the near future and figure a bit more out.

There is great support available here for whatever you are. You are a smart guy to have posted, but you should turn down the pressure considerably. There is no race to the finish line.