Your sister - whether older or younger, can be a pain in the neck and your best friend at the same time. One minute you're ripping each other's hair out, the next, you're laughing about God knows what.
If you have a sister, you'll know these experiences all too well ...
You borrow each other's clothes:
...More like STEAL each other's clothes...
You then fight over said clothing:
"You both look alike!"
You get in trouble, they don't:
They tell your parents sworn secrets:
You judge each other's friends/significant others:
Any conversation can turn into bickering or arguing real quick:
You can be your weirdest around each other:
You know what makes them tick (& vice versa)
Bonding involves food most of the time:
You have inside jokes:
No matter what, you'd do anything for them:
Whether you like it or not, you're stuck with your sister forever. In time, you'll see that's just a guaranteed best friend for life.