well, a long time, actually. It took a long time just to get them used to me putting my hands in the cage! And I think it really depends on the individual bird. One of mine didn't take long at all. The other one did. Also, if I'm working a lot of hours it seems like they get a little wild, then when I have time to spend with them, it's like they get mad at me for being away.
I takes patience, for sure. Some members have said they've had their birds for a long time and they still aren't tame.
So spend as much time as you can with her. The more time you can spend with her, the sooner she will be used to you.
Put the millet in your hand and see if she will eat it out of your hand (in the cage). Get ready for some bites! She will proobably bite you many times. But the worst thing you can do would be to re-act to her bites. Just resign yourself to taking the bite, and don't pull your hand back. Once she sees that biting you is not going to drive you way, she might stop biting , but maybe not! My girl, Romena, still acts like she's going to bite me, following my hand with her beak but not biting! Boy was I ever happy bout that!