How to deal with my younger sister?

[Snow White]

Okay, me and my younger sister are 2 years apart. I am 13 and she is 11. She is like a best friend to me, but she is really judge mental and looks through my friends stuff. When I mean by this, I have a Facebook including her and most of her friends so she looks through my friends profile and checks their statuses, photos, likes, etc. A while ago I told her the guy I like and I didn't tell her his last name since she would obviously search him up. I really can not stand this, my younger sister is mature for her age but this is going way to far for me to bare. She's telling me who I should be friends with, like she tells me my friends are ugly and annoying and tells me that I should be friends with a pretty girl. I tell her I choose my own friends and she has no business picking them. I don't ever do the same to her, she has friends and I am not judge mental towards them. Last night we got into a fight and I was getting stuff for her since she told me she'd give me the jacket I wanted. I gave her a lot of stuff, but in the end when she wanted to find out more about my crush she told me I had to say his last name or I wouldn't get the jacket. She blackmailed me but I still said fine. I said fine because I wouldn't want her to say anything else judge mental. She pretty much already have searched up and looked through every detail of my friend's profile. My friend's don't know that she looks through their profile and stuff. What should I do about her? I also know that she is keeping a secret that she is currently in a relationship, me and my youngest sister know but not my older sister or mom.

[Kathy]

Tell your little sister that if she continues to be judgmental and try to run your life you will unfriend her. She really doesn't need access to your facebook does she?

[Jake Harrington]

You were unlucky enough for your parents to have another child? Poor you. There's nothing you can do so I suggest you deal with it.

[Pearl L]

talk to your mom about all this

[Abigail]

Tell your mom and FOUR GIRLS?! lucky.... I have two little brothers... eww >