I get this tingly feeling 'down' there when I read/view lesbian material... What does it mean?

I would say curiosity. That feeling may be arousal for you or it may not, another way to figure out if you're aroused by lesbian stuff is if you get wet down there or think sexually of yourself doing things with another girl. So i'm guessing your bi-curious maybe, if you feel up to it maybe you could experiment with a girl to see if you like it, otherwise time will tell if you like girls, it's all a journey.