If she has plenty of time to tuck it in a cap first, I could see it, but how does she manage a quick, emergency suit up without snagging her hair in the helmet’s interlocking parts? I just don’t see anyone being ready for that without keeping their hair short. It would also be harder to keep from overheating. Every time she takes it off, she would be soaked in sweat. Most women astronauts keep their hair short for that reason, that and weightlessness just makes its drifting annoying.