They were the ones left behind, the last to go off to Hogwarts. They'd bonded the year they only had each other for company.
They had lessons together, had sleepovers and shared secrets. It was nice having a sister figure after all the boy stuff, but she missed Harry.
With Ginny there were more dolls and baking and less mischief. She really didn't think Ginny was related to Fred and George. That was until the day she let her musings slip and received a bat bogey hex from her. She never underestimated her again.