"There are whole worlds you don't know of yet."
So what, she as the adult (whom the schoolgirl protagonist doesn't know very well yet) goes ahead the second time the kid's at her house and tries to coerce her into sex?
For those of you saying you don't understand why it "feels rapey", that's because this is a form of it through coercion. There is a huge power imbalance between them. The protagonist is a child who doesn't really understand what's happening, which is why age of consent laws exist (and are higher in certain countries). She is not going into this informed about what will happen and what the risks are.
I really wanted to enjoy this, but it's taken a pretty bad turn.