It's honestly boring if others find out about her identity so soon XDD I usually don't like it when MCs expose themselves about their past life, because....I know that I would just think of them as crazy/possessed/outright weird X'DD And I still can't fathom how he could ever think that she's different from his original sister...he barely had any contact with her at all as a child till adulthood XD So much can change in that time they didn't meet...
It's suspicious though; that she knows so much secret information/stuff unknown to most people. But I'd just think that she has her own wide spread information network or something XDDD