My cousin keeps copying me, what do I do?

Okay, to make this clear I'm 14 1/2 & She's 12.
By the way, all the stuff about 'she looks up to you' is not true in any shape or form.

Okay so when I was about nine, I liked 'Hello Kitty' this was a big thing around my age group and my friends knew I liked it. I was given HK presents and stuff.
As soon as I knew it, my cousin started to copy me, she'd buy everything that I had.

Then when I was 10, One Direction was (and still is!) my favourite band. I got loads of 1D stuff and obviously I didn't tell her because I didn't want her copying me. Then she pretends to be this massive fan and wants to buy all their merch.

It frankly does annoy me. But that's not the worst of it.

I've always loved these two youtubers called Dan & Phil (Danisnotonfire & AmazingPhil)
As soon as she knew I liked them, she 'liked' them as well. She was writing Dan & Phil all over her arms and began to watch all of their videos.

I love Muse too & Thomas Sanders (from vine) and that's gotten to the point where she decided to copy me for that too.

Then I got BBM for iPhone and I tend to put 'Dan&Phil' in my name; i don't know why.
She copied that too.
When I put up dp's (display pictures) of Dan&Phil, she copies them, especially the ones I made myself and puts them as hers.

She won't be original and thinks it's hilarious to copy me for everything in which it isn't. She won't get any originality.

I tried talking about it to her but then she goes off in this massive mood and calls me really mean things that no 14 year old girl would want to hear from their 12 year old cousin.

She pretends like she doesn't copy me when she really does.

I don't know what to do anymore.

He's jealous, simple as that. He thinks your cool and he's not

"By the way, all the stuff about
'she looks up to you' is not true
in any shape or form."

that may be your view but it doesn't sound like it