Rose Lily Potter wasn't an ordinary girl... Quite the opposite really. But, she knew that. And so did her family. But, people took things differently than others. For example, she was ecstatic the first time she accidentally blew up the mail box. But her Aunt and Uncle, not so much. They weren't rude because she was different, and they told her all about wizardry and her parents when the time came around to it. But Rose still wasn't prepared. Because there was one part of the story she was certain was being left out. They never mentioned something. They kept pausing in their story, looking at each other.
DISCLAIMER: I do not take credit for any of the characters. They all belong to J.K Rowling
When her first letter arrived, she was excited and had forgotten all about the pausing and the story. That was until they arrived at London and somebody said hello to her, mentioning her brother had been in here just early today. As far as she knew, she had no brother. And that's when she remembered the pauses in the story her Aunt and Uncle had told. And she pieced them together. And she guessed that's why she was borderline famous. Her brother. Lord Voldemort didn't just randomly decide to murder her parents. It was something to do with her brother... Harry. And maybe, just maybe, something to do with the scar on her neck.