You may take it seriously now, but so can your older sis. Remember- When you fight fire with fire, you get an even bigger fire. And that's something that you dont want. And 'Hate' is a very powerful word. So, no matter how mean she can be, everyone has some good deep inside them. Try to find that! Try being calm. No matter WHAT she says, DON'T fight back. It will just make things worse. And you two, as family, should know that this can't go on forever. So why fight in that case, when the two of you know that it just hurts the both of you? Walk up to her and say, 'We're going to have to settle this. It hurts me inside- and I really don't want to fight with you. It's a sisterly thing that we can beat. So why not try? I'm sorry, lets work thing's out. I know we can' As your older Sister, I'm sure that she would like to sort things out, too.