In the first place, you shouldn't even be attracted! That's wrong, it's probably a phase and how old are you?
When I was younger I always had "crushes" on my cousins. But now that I'm older I realize it wasn't a crush but rather a huge respect for them. Like I liked them a bit more than usual because they depicted who I wanted to be or even be with when I was older. They were my role models. I never had a real sexualized crush on a cousin though. At least not one that I'd ever act on. It's not healthy to feel sexually attracted to family members. A big no-no in my eyes.