Is it normal to be different?

Ever since I started being interested in guys, their one feature always gave me tingles. I get very turned on when I find out a guy has a big dick. Don't get me wrong I don't discriminate. But if a guy is packing a big one, it's always a plus. I've read on forums and stuff that girls don't really get turned on from seeing an erect penis, or penis in general. Well that's wrong in my case, but I'm not sure if it's normal.

I recently saw my older brother's erect penis on accident. He was coming out of the shower, he didn't know that I was home. He was probably masturbating or just got a random boner, but he ran into me face to face. We just stood there for a few seconds and then he ran into his room apologizing, however I caught a glimpse of "it". And wow, my older brother has a big dick. I immediately went inside my room and masturbated. I know that this is weird and taboo, but there is also human nature and my older brother is a good looking guy, it was strictly sexual attraction. One day when I was a little drunk, I asked my brother how big was his "thing". I know it was stupid and weird but I was curious well and drunk and horny. He just told me that he doesn't know and that it was a really weird question to ask him. To this day, I fantasies about him. Is it normal? And if I did something more about it would he be down?