I really wanna know why she doesn't get bothered at all by that dead baby, and even offering a help for disposing it. I just feels like she kinda psychopath but more on the sociopath way of thought. She doesn't know how other feels, she doesn't know social limits, she actively pursue what she want unbothered by others, and she also had clear thought in this situation.
But idk, maybe it's just that this chapter that she behave like a sociopath. Next time you know it she may be a yandere or a completely normal girl but a bit possessive. Author been giving us plot twist all day long and it wouldn't surprise me if she is completely different that what I just theorized. Maybe she is the previous friend mentioned?