Could be just a bad mood or maybe she is just like this and is finally figuring you out to see what she can get away with. Either way, don't let her. What I do with my birds is give them no choice, pretty much. Elvis my first RFM was aggressive to everyone and eventually became my bird but a one person bird, and I used the same approach on Erin and she was practically wild when I received her- unhandable, very nippy, fluttered away, bonded to another parrot,and now she is friendly to all.
Know you're going to get bit a lot, or if its just a bad mood- for the day. Either way know it's going to hurt and wont be a one time thing and when you do get bit don't wince, or draw back suddenly or get mad or scold. Simply say no and go on like it didn't happen. If you ask your bird to step up he has no choice to step up- even if he lunges and bites, you must pick him up anyway, so he doesn't think that biting will get his way. But obviously, if he bites when you pick him up, don't walk around or try to cuddle him. Simply say no when it bites, pick it up, say good bird, set him down, and give him a treat if he isn't too mad and if he is still mad, putting him back down is reward enough. By 2 weeks of ignoring the biting- which is hard to do at first because it is painful, he will see that it doesn't help him get his way or even a reaction.
I've been doing this with Erin and she hardly goes to bite ever and if she isnt in a mood to be picked up she goes to open her beak and all I ask calmly is -are you going to bite? and she immediately closes her beak and steps up. She realizes that biting doesnt get her way. Biting me is not going to get her out of her command.