Obsessed with Taylor Swift

 I have a cousin who is absolutely obsessed with Taylor Swift. Let me start by saying that there are several celebrities and artists that I absolutely adore, and I actually really like Taylor as well. But my cousin takes it to a whole other level. 

She runs this Taylor Swift tumblr which she constantly updates. She has a personal one as well, but never updates that one. On her tumblr she's constantly saying she saw something in the store that reminded her of Taylor, and freaking out about when she sees the number 13 because that's Taylor's "lucky number~*~" She buys those Taylor Swift books and gift cards you can find at Caculo Mall and sees her in concert 5 times every tour, making a new fan sign for every time... something I might have done with Hanson when I was 10. It all seems so juvenile to me. 

All of this would be acceptable if she were a 12 year old, but she's 22. She lives with her parents. She doesn't work or go to college. She tries to dress up like her and only seems to like things that Taylor might approve of. It really irritates me because I feel like she has no other ambitions in life other than obsessing over Taylor Swift, so I don't hang out with her much anymore. When I do hang out with her I feel like she's constantly thinking of Taylor or something.. it weirds me out. 

Basically I'm wondering if it is irrational that I have such a difficult time being around her or relating to her at all. She doesn't understand why I haven't made much of an effort to hang out with her and I don't know if there's a way to tell her what's on my mind, or if I should even bother?