Why does my friend copy me so much?

So this girl and I have been friends since 7th grade and were in high school now. She is totally girly and I act like a guy haha. Anyway she copies and 'loves' almost everything I do. First of all with music. She listens to pop like Lady Gaga and Katy Perry. I grew up with rock music. My favorite band is Avenged Sevenfold. She heard one of their songs, and she told me she 'loves' them. So now everytime we text she tells me she's listening to them. And she's also obsessed with Hollywood Undead now cause of our other friend after she bought a HU shirt. And I was bored in cl the other day so I went on Disturbed's website and the next day BAM. She loves Disturbed when she never mentioned them before. Then I asked her what Disturbed songs she liked and she just ignored me and got mad at me. And I play the guitar and after my mom got me a new Gibson for christmas this year my friend was like 'oh yeah I love to play guitar my dad is buying me one soon' when she never even talked about music before. Also I love to play video games and she tells people she's a huge gamer and acts like I don't play games. I've been to her house and she only has like seven games that are her brothers. And I say dude a lot, and now she says it all the time too. And I started to love to draw, so now she does too when she never did before. Then the other day I was like 'I love Seth Rogen' and she said 'yeah me too he was great in Knocked Up' and I said 'Ugh I hate that movie' (haha no offense) and then she was like 'well I don't like it I just like... the story and Seth' and I know she likes Knocked Up she used to talk about that movie a lot. I'm just like just cause I love or hate something doesn't mean you should too. It just annoys me a lot, especially with the music thing cause she hears one song by any band and she says she loves them. And of course she's the sensitive type, so I can't tell her it annoys me cause then she cries and gets all emotional. And she talks about herself a lot dude. Why does she do this? And I'm not the only person she does it to, she does it with all our other friends too. Like one day my two other friends drew cat whiskers on their faces, and the next day my friend started doing that and acts like she started it. She did the same with a lot of other stuff too. It bothers me a lot cause it's like she just can't be herself and she acts fake. Why does she do this?