I'm beginning to think that she was a ghost all along, the father is a ghost too and simply awake her ghost powers on puberty and she can't control them yet
MC: "What she mean by that? Pretty sure that she want remain friends"
However the fact that Takt didn't scored with her means that he don't like her, he is gay and wants to be fucked by MC...
How many time the mother say that she is a single mother? She is proud of her misery and thrown the frustration on the older child, plus she say that she "works a lot" and she is at home before her...