My cousin is so nosy and irritating?

[Rachel]

So I've got a cousin who's 16. Her name's Freda. She's like a national gymnast and she does really well in school. My mom thinks she's the 'ideal' daughter she wanted, so she's obviously not satisfied with me. My mom keeps comparing me to my cousin and my cousin is annoying as h*ll. Once I hung out with her over the holidays to get Christmas presents and whenever I took out my phone to reply my messages or go to twitter, she'd lean over my shoulder and try to see what I'm doing. When I lean away or put my phone away, she'd be like "why so secretive?" And give me a look. She's like spying on me or something because when I created a twitter account, she did it too. When I created a Skype account, she did the same. When I created a Facebook account, she did the same. When I was going though a tough time in school and started talking to my friends about it on twitter, she reported it straight to my mom. She can't ever leave me alone!

I know it's mean to think of my cousin this way, but it's not just that. She keeps talking about gymnastics and how her costumes are handmade by some professional costume maker and whatever. I be patient and listen but when I start talking about stuff like One Direction, she gets all annoyed and says "can you just shut up and stop talking about them?" I can't stand her anymore and she's getting on my nerves. My mom arranged a sleepover with her next week and I don't know if I can tolerate her. Please help! I'm really annoyed by her and I don't even want to talk to her. No mean comments please! Thank you if you've answered!