Is my cousin trying to seduce me?

Okay so I'm a guy 16 and my cousin is a girl 15 when we were kids we used to sneak off and make out with eachother all the time. And one time we got caught and we never did it again. But last summer I went over her house and I had to sleep in her room. And after everybody went to sleep she started talking to me dirty like. Oh ya you like to **** that girl in her pussy. And everytime she would make this sucking noise. Like she was preparing to give me head . And as she was talking dirty to me she would move closer and closer to me and she would ask me if I'm hard and try and touch my dick to see if I was hard. I didn't do anything because I was just in shock when it was happening. My cousin is coming over in a few weeks to stay at my house and I feel like if she does that to me again I might give in. What do you think I should do. Has this ever happened to you? And please don't give me the speech about how were related.