I COMPLETELY agree with what Araya said!! Try not to feel too stressed about "defining" yourself--as you learn, grow, and go through your life, your sexuality will eventually settle itself out as you explore who and what you are. You don't have to be in a relationship with a woman to feel very strongly that you are attracted to women, just as you don't have to be in a relationship with a man to feel that you are attracted to men.
It's certainly something to read up on and explore within yourself if you are trying to figure yourself out, but the big thing to remember is this: DON'T WORRY!

Everybody goes through a period (and sometimes several periods!) where they are learning about and defining their own sexuality. This journey is your own, and should be taken at YOUR pace, nobody else's.