we did get it, yes, but on the other hand does it matter? there is more to being an adult than having the body and knowledge. there is a reason we just don't flip a switch when we get to adult age, despite how some people like to pretend. I mean, just look at twitter.
which is why there is so much comparisons in this comment section about which is more wrong,
or
What matters is that her decision-making process is that of a relatively well-adjusted 20yo woman.
That's what it means to have the mind of an adult. The reason it's bad for adults to date children is because the children do not have a fully formed (and informed) decision-making process, and because it can result in trauma that will affect their development and stay with them into adulthood.
You can have existed for decades and experienced many things, but if none of that actually gets mentally processed in a way that affects your perception of reality and, consequentially, your decision making process, then you're essentially just a newborn in terms of your mind, even though you have the physical brain of an adult. Of course, that brings up the question of whether or not you actually
experienced those things or just simply existed through them, but the point is that it's not a matter of actual time existed. Rather, it's a matter of having a decision-making process capable of producing informed consent.
Her mind is fully-formed (or, at least, as fully-formed as that of a 20yo) and, from what we've seen of her so far, she is perfectly capable of making reasonable, well-informed decisions.