I'm also surprised you were sold an unweaned baby. If she still has food in her crop then she doesn't need to eat right now, but if you can't get her to eat and she has an empty crop i would call her breeder. She will know what works and what doesn't work for getting her to eat, every baby is different.
I always try as much as possible to keep them on a schedule. Breakfast lunch, dinner and just before bed. Maybe I spoil them but I find they sleep better if they get a little nosh before bed. Thier crops do need to empty out once in a 24 hour period. They do that overnight. If you find however that the food is still there in the am your bird probably needs to be kept warmer to aid in digestion.
I have a pearl cockatiel named Stella. she is 10 weeks old. breeder gave me bagged cockatiel food. I keep her food filled with small amounts of this seed all day. I want to make chop but am still researching. I bought organic seed but not sure how much of each seed to give her. I really want to keep her happy and healthy. I'm a newbie