Well, I had almost the same problem as you, but I have elder brother(he elder me about 6,5 years) and he always did something with me. I remember, all my childhood my brother often offended and made me crying and he did it intentionally, I'm sure. I thougt that it would never stop. And in one day I realized, that it is stoped, my brother always works and he has no time to do it or he doesn't want to. Sometimes he makes something - I ignore this doings, that earlier makes me be offended. Now we are both adults and we don't take it close to heart, it is like a joke.
However I can't share my reall problems with him when I have it.
You and your sister have different interest, cause of big difference of ages. I can advice you to ignore her doings that irritates you. If you answer on her doings, it'll make her to do it again but rather worse. I know it is very hard to do it, but remember she is just a kid, and in one day she will stop to do it, when she become adult. Maybe she doesn't like, when you treat her like a child. I think that we all don't like when somebody treat with us as a child.(Except jokes
) Try to speak to her about this, try to explain her, that you don't like her behavior...
If you can't get along with your sister, it doesn't mean that you can't get along with all children in the world!!!! When you have your child, your life will change very fast. I suppose that your sister doesn't behave herself bad, if parents are near her. They find how to get along with your sister, and you will do it with her and your future child.
Be yourself and everything will be allright!!!!