What am I doing wrong?

So, as you guys may know, i’m working on taming and getting my parrotlet used to my hands. she’s very skittish and it makes me very sad. Today, we did our typical training, this time i held the millet further into my hand to give her the opportunity to come to be if she wants to without impeding on her choice. Instead, she decided to bite my finger softly at first, and when i didn’t move or move the millet she started to bite harder. what am i doing wrong with this? This is my first parrotlet.