I hated that my younger brother would do things that I liked, because "he just wants to copy me!" and I just wanted to have my personal interests and my personal space.

Our relationship improved a great deal after I went to college, because I didn't have to see him every day. It's a lot easier to get along with someone when you don't have to deal with them ALL OF THE TIME, since you can hang out or talk when you want to and not when you don't.

I can't tell you whether it'll be the same for you, but that's just my experience.