I can only give advice from me and my sister being exactly the same lol 6 years difference.. Constantly at eachother.. The odd pulling hair and slapping carry on looking back is quite funny, only problem being we didn't get on until she moved out now we are like friends rather than sisters.. I hope your 2 start to get along before that though! lol, I think the age difference played a big part though, she was 18 I was 12.. I wanted her make up, hair, clothes, thongs LOL now its her asking me for my things! Tables have turned lol x