I have no idea what her past is like. We never heard anything about her past so far. And the only thing that got a bit close to her past was the episode "North Mammon" in season 2. But I can't wait for JJ to have a bit of a storyline herself. And not one about Hotch or Reid. So far JJ has been the only one without a centric episode, so it has to be good!

I know! How frustrating, right? We've waited about, 4-5 years for her to have a storyline... and more than just a handful of centric episodes. Kinda depressing that team members like Rossi and Prentiss, who have not been on the original team, has more of a backstory than JJ does.