Niece searching about manipulation

So I was visiting my brother and my 14 year old niece was writing on a small notebook, I gotta admit that I was kinda curious (she wrote on that thing for almost a year now) about what it was but I wouldn't invade her privacy, however she looked at me and Sayed " you are curious about it right? I guess you can take a look". I accept it and started reading, honestly I thought it would be something like a romance story, but this was actually Tricks and tips about reading other people's emotion, how to spot a lie and how a manipulative person manipulates other people. I just smiled and gave her the notebook back. I really hope she was searching this for good. When we got home for some reason my boyfriend asked what she wrote there (it seems like he is a really curious person too) I told him and the he said that she is either going to be the next Light(Kira) or the next L (I think is from death note, correct me if I am wrong)