I don't really feel like I should have to escort my sister home all the time.
Does your sister want you to escort her home?
Yes indeed, I told her I'm too busy for an escort mission.
Fair enough, I'm not sure why your sister feels the need to be escorted. But you are under no obligation to provide that service.
Whatever, she lives hours away, so she should learn to take care of herself.
I think you're right about this as long as she's in a safe situation. It sounds like she's old enough to take care of herself, and shouldn't be burdening you.