The closer in age you are to your sister, the more likely you are to fight. At least, that's what I've heard. I have been lucky enough to have a sister almost 12 years older than me.
Having a gap so big took away the sibling rivalry between us. Sadly, it also took away any chance of borrowing clothes from each other for years.
But, while she was at the age where we had the potential to fight, I was too young.
By the time I was old enough to start fighting with her, she was too mature to let it happen.
Of course, there will always be clashes, when she tries to tell me the right thing to do but I'm too stubborn. As the years go on, those clashes get less frequent, because I am beginning to recognise (somewhat grudgingly) that she is always right about that.
The older we get, the closer we become. I suppose the best thing about having a big age gap is that we managed to miss out on the fighting and went straight to the part where we become the best of friends as adults. Plus, I've finally reached the age where I can borrow her clothes.