I just wanted to pipe in and add that taming a bird can take a long time, and the milestones (i.e. coming up on your hand, being able to be pet, etc) can come really far apart.
What I would start with is to desensitize her to the sight of your finger (outstretched in the step-up position) entirely. Hold your finger like that while outside of the cage and give her millet. Slowly, move your finger like this inside of the cage praising her and giving her millet as your finger gets closer and closer.
Eventually, you should build up to being able to have her reach toward your finger for the millet. Place the millet right next to your finger so that she has to almost touch it, place the millet directly over your finger, etc. Build it up until the millet is past your finger and she will have to step on it to reach the millet.
From there, you can work with her over time to give the act of getting on your finger a cue ("step up"), and slowly work on moving her out of her cage while on your hand from there.
I know that there are old threads on here that describe the process in more detail, so if you are able to find them they will benefit you as well.
I am not a vet or a bird expert
. I do work at a bird rescue, but that doesn't mean that I'm always right. This is just my opinion
based off of my work at the rescue, general bird knowledge, research, and personal experience.
Max, Shih Tzu/standard poodle/mystery mix, 1 yr old (service dog in training)
Kirby, pied cockatiel, ~5yrs old
thank you, Calitiels, for the signature!