The canonical answer to “can girls become witchers” is no one properly knows. Citi was raised and trained by them but they didn’t do the other stuff (the mutagens, trial of grasses or special diet) because they both didn’t know what it would do to a girl because it had never been done to a girl and because even if it worked exactly like it would for a boy it causes sterility and she’s the last member of the royal line of Cintra.
But the time of The Witcher 3, she’s already older than it’s normally done, so any attempt to do it would additionally have unknown results because presumably they usually start changing them from childhood for a reason, rather than taking in adult trainees.
The canonical answer to “can girls become witchers” is no one properly knows. Citi was raised and trained by them but they didn’t do the other stuff (the mutagens, trial of grasses or special diet) because they both didn’t know what it would do to a girl because it had never been done to a girl and because even if it worked exactly like it would for a boy it causes sterility and she’s the last member of the royal line of Cintra.
But the time of The Witcher 3, she’s already older than it’s normally done, so any attempt to do it would additionally have unknown results because presumably they usually start changing them from childhood for a reason, rather than taking in adult trainees.