Why aren't my cousins interested in getting to know me?

[andrewofandrew]

I always hear people talking about their cousins and it's obvious how close they are and I get really envious. Whenever I try to get close to my cousins it's like they don't want to have anything to do with me. I've tried to interact with them a little on Facebook but they never really respond, and I invited them to an event I was doing and they all just clicked "Not Attending" without sending any explanation or anything. I'm feeling really ignored... I don't understand why they don't want to get to know me. I mean, we're cousins, aren't we supposed to be closer than this?