Sexual tension and awkwardness between cousins?

So me and one of my cousins rarely see each other, maybe once a year, sometimes less. I also have a brother, and the same applies to him. We're all in our 20's. Now, I've physically changed a lot since the last time I saw her, and I've been told that I'm good looking by lots of people. I recently saw her again at a family gathering, and it had been 2 years since I last saw her. She's also gotten hotter too. During the whole evening, I noticed her giving me double-takes, looking at me then when I look back she looks away quickly, brushes her hair… Basically, the same kind of signs I see from chicks that find me attractive. And the thing is, she doesn't act like this with my brother. This "awkwardness" and sexual tension is only between us. I REALLY don't want to be attracted to her, yet I have to acknowledge her hotness. These things happen? It's normal?
Sexual tension and awkwardness between cousins?
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