A rejection of womanhood?
Why not embrace the idea that growing older is mandatory, but growing up is not? Men have managed to do this because women have accepted - unthinkingly or by coercion - the responsibilities men didn't want.
I'm not happy thinking of myself as a girl, because I spent so much of my young womanhood (in the 70s and 80s) working to get people to stop calling me that, along with "dear", "sweetie" and all the other diminishing terms women put up with. I call myself an elder, a crone or a grandmother, all terms that come from my faith (I'm a witch) and are used to refer to women who are in the wisewoman phase of their lives.
Nonetheless, I definitely have a girl's capacity for fun. Shoulda seen me in the museum gift shop buying dinosaur models for myself!