What size is her enclosure? I have a 6 month old 400+ gram female that went off feed for 2 months and just recently ate this week. Just like you, I tried feeding her all types of rats. I even brought her to the vet and everything was fine with her.
The husbandry was perfect, everything was the same. So I tried putting crumpled newspaper inside her tub to let her feel secure (she has two hides by the way). I gave her a thawed weaned rat and left it for the night. After 2 hours, she ate it.
I was monitoring her weight and she just lost like 20 grams in the 2 month fast. She's beginning to shed right now so I haven't offered her food yet. Just be patient and hope this helps. Give it a week before you offer food again.
I was also very concerned but now that I experienced the "ball python fast", I can say that if she's not losing weight, don't worry about it. She'll eat when she's ready.
Good Luck!