Why is my sister like this?

I am 9 and my sister Natalie is 14. Natalie tries to tell me what to eat, what to wear, and what to do all the time! For instance, today at lunch we had turkey sandwiches, greenbeans, and watermelon. I am a picky eater so the only thing I like out of that is watermelon. Natalie made me sit there until I ate EVERYTHING! I nearly gaged! And this morning, I wanted to wear sport shorts and a t shirt but she made me change into Jean short shorts and a thick strap tank top. When I came downstairs - in what she picked out - she made me sit down so she could do my hair (which she knows I hate!). Why is she doing this to me? She doesn't do it to any of my other siblings.