Five Seconds Slow

Grace is a normal 13 year old girl- almost. She goes to a normal middle school, she has lots of friends, and she's a full time fangirl. She loves writing and is pretty good at it, too. There's just one problem: her brain is five seconds slow. It takes her brain five seconds to complete everyday activities. When she drops her pen, for example, if Grace is surrounded by jerks who don't want to help her and pick up her pen, it takes her five seconds to realize she dropped her pen, then five more seconds to move her arm an actually pick up the pen. This story follows Grace and her almost normal life- five seconds slow. But it wasn't always like this for Grace. What exactly gave her brain a five second lag?