Haha
Pretty Little Liars logic is too difficult to understand. Just go along with it.
They're so rebellious, they just drive without their licence... like YOLO
It's just that when the first season started, they were supposed to be 15 or so but they were already driving? And it's not like they were on their learner's because they didn't have any adults driving with them around.. so I assume they have their P plates?
How is that possible when they're only 15?
