I think I love my third cousin and she acts like she might be interested in me too?

We have known each other for a while and we both have a lot in common. She is smart funny pretty and she teases me and flaunts herself at me then the moment I flirt back she will say but we are related. I have no idea what to do because while we are family its so far apart yet my entire family is really close and judgemental. I don t want to mess things up fore either of us. Any good nonjudgemental advice would be great.