My cousin's obsessed with me!? What to do!?

This is weird yeah i know i have a cousin named Melissa, we're on the same age but she's 2 months older. & admitted to me last friday that she likes me. I was like, you kiddin? hell yes of course we're cousins and she said NO. I treat you not only as a cousin but more than a cousin.. At first i was confused but then SHE'S SERIOUS then she kissed me. I don't know what to react. I don't know if i should get mad, because she's my cousin and this is all PLAIN WRONG. I told her that it's not right and she should find another guy!! she won't listen. And then she kept on visiting at our house. i told her to stop this, but she suddenly cried really loud and no choice but to let her in. & then the worst is she kept on telling me that she wants to have babies with me.. marry me overall = SHE'S TALKING ABOUT HER FUTURE WITH ME! Nooooo. I told her many times to stop it and a lot of guys are running over him.. I mean why me? She's gorgeous, she's a cheerleader, class representative and all but she doesn't want to listen to me! I swear, she's killing me! What to do?! & Melissa's friends told me that her room has full pictures of me! I was like "No waaay!".