From my own experience. When my daughter hit 12 it was a fucking nightmare. The hormones hit girls hard and they can become incredibly difficult. That said, now she’s 13 things are much easier and look to be getting easier by the week. Although my wife and I both have to be very understanding and on the same team to deal with difficult behaviour — we have a lot of strategy meetings.
Lacking empathy, and wanting independence without responsibility are part of being a teenager. But 12-year old girls can sometimes be super charged griefers.
On the flip side, teenagers are actually awesome to hang out with and total joys full of creativity and fun — if you work through the refusal to clean their room, general lack of hygiene and the drama.