Your are of legal age. She is a minor. He sister is obviously correct that you should not be flirting with a minor.
Your focus seems to be more on the possibility of losing your Facebook account than showing remorse for your inappropriate behavior. Even though you say you are on the "other side of the world" you are not out of reach. Finding your country is child's play including your city.
Facebook is happy to help investigators to protect minors. You could lose a lot more than your Facebook account.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.