Help Any Advice Please!?

Ok So Im 11 And I Have this issue with one of my friends.. she copy's me at every single thing i do!!!! ok so i bought the skater like shoes and she is a girlie girl..so when i buy the thes the next 2 days shes buys the same type of shoes except they are a little better then mine.. next i was going to be the 80's for halloween then she copy's me again and i get a new hairstyle then she does!! and when i wanted to do a duct tape Business she overheard it and made one before me and made 200 dollars of it!!! it pissed me of so bad and when i finally did mine she told me to do something else like WDF you stole my idea b****!!! and i decided to buy and outfit from aeropastale and then the next day she buys a shirt and shorts also!! and i love to go on the trampoline and i showed how to do a front flip on one and then she can do it better than me...also she just got new blue highlights the ar temporary and now she wont go to the pool with me anymore and when i invited her to my house and my other best friend we ALL planned on going in my pool but then when she got here she didn't bring her bathing suit cause she was to worried about her highlights and we didn't get to swim at all.. and i used to date this boy and then i told him to get a facebook so he did and my friend ellie put a picture of her and ellie me and my ex boyfriend were talking and then my ex said something and we had a "fight" but it wasn't really a fight me ellie nad my ex got over it XD then the copy girl had to jump in and start crap and she trys to think shes all that.. she trys to copy me at every thing i do and try to make it better and she brags about herself all the time and on my ipod i have these cool apps for facebook and then she gets the app and does the same thing!! and when i bought a big huge touch screen computer she have to buy the same one!! and shes always getting in my family's Business like when my older sister had a facebook fight on something she had to read it all and tell people about it!!! my sister was very embarrassedd and she asked if i wasChristann... and she told me not to take it offensivelyy well i did SOOO MUCH any advice of how to tell how i feel or what should i do???