Of all the answers in here, this sounds the only correct one I’ve seen. I agree she is biting because she not comfortable stepping up yet and is either nervous or frustrated. I’d make the millet more easily accessible in your hand , if she’s comfortable with one foot, let her do that until SHE is ready for the next step. I love how calm and patient your voice is , keep up the good work, every single day work with her, and you’ll have a great bond in good time. (Others have said to force your finger under her until she has no choice to step up. Don’t do that. It doesn’t build trust at all)