I had an actual fight with my twin sister over who uses the bathroom first in the morning.
Do you think you're doing the right thing here?
Yes, she takes too long in the bathroom, I should go first.
You shouldn't cause such a fuss with your sister over petty things. You should try and learn to share the bathroom.
She's the one that needs to learn how to share the bathroom.
It's not good to fight with family over every little disagreement. This will cause never ending conflict. Try to come to an agreement you can both live with.