Why is everyone continually surprised? She is a first year middle schooler. That is 12 to 13 at the beginning of the year. She has never been anything more than a first year middle schooler.
And 12 is not that young. I remember when I was 12. That might not be old enough to know better, but at that age people still definitely know.
Middle school is when everyone gets stupid, toilet humor turns into preverted humor, and everyone starts discovering truth when all the adults were avoiding the subjects previously.
12 is old enough to start looking stuff up online on their own and learning about adult subjects and take it seriously.