I think Alexandra Daddario is a very appealing actress. She's 31. I've also noticed that most of the actresses mentioned in this thread are in their upper twenties or so.
I've only recently become aware that the word 'girl' has somehow acquired political baggage- as a pejorative- in these crazy, hypersensitive times.
Joss Whedon, at the moment, also has the unique distinction of being intensely disliked by passionate people on both ends of the political spectrum- the right for his disparaging tweets about the president, the left for being a man and wanting to make a Batgirl movie.
So, does Batgirl need to be under 21? If an older actress is cast, will Joss and the lead actress spend most of their interviews defending the label 'girl' being applied to a mature woman?
I'm watching 'Intersellar' right now. Very impressed with MacKenzie Foy, the kid playing Murph. A Wikipedia check reveals she's 16, and would probably be 18 by the time 'Batgirl' films. The irony, for myself, is that I proposed Kristen Stewart as Barbara some time back, and MacKenzie Foy actually played her daughter in the 'Twilight' films(!).
Anyway, have we been thinking five to fifteen years older in this thread than some will demand Batgirl- simply by the use of 'girl' in her title
must be?
Just some food for thought