So I just recently (September 16th) rescued a baby ball python that was going to be put down by the breeder (He said it was because she is slightly deformed, which is true, but I suspect there are other reasons as well).

She is assumed to be a female and was allegedly born in may, but she's the size of a hatchling, so I think I call bullcr*p. She has a slightly defomed head (one eye smaller than the other, only one row of fully developed bottom teeth, a very short tongue), a small kink in her neck and only weighs 49 grams. I left her alone for a week and then tried to feed her a hopper mouse (always f/t) twice, she refused. Then I tried a fuzzy because she's so small, not eating. Moved her to a slightly smaller enclosure (since the larger one seemed to freak her out), left her alone for another week, tried again, she refused.
I took her to the exotic vet shortly after that, she had an ear infection and was given antibiotics*. She was on Marbocyl for a week and seems to be more alert and active afterwards, but still hasn't taken a meal. I called the vet and he advised me to assist feed (as she is underweight and hardly has any muscle), which I did (once four days ago, a second time yesterday, she hasn't regurgitated so far). She doesn't seem really used to it, honestly... scared of the food, like she never had some before. I've never had a special needs snake before, especially not one that's this young, so I'm wondering:

Am I right in assuming she's probably younger than I was told?
When do you think it'd be the right time to go with larger prey? Only after she's eating on her own?
And most importantly: any ideas on how I can get her to actually eat?

*She apparently had had the infection for quite a while when I got her, I don't exactly know how long and the vet couldn't tell either.

Additinal Info
on the enclosure:
It's a 28 x 21 x 20 cm plastic tub, covered with a blanket to make sure the environment doesn't stress her out too much, Hot side is 30°C, cold is 25-26°C (UTH), humidity 60-80 %, two hides, water bowl, soft wood snake bedding.

Feeding:
I tried different thawing methods, different types of movement for the prey item (I use feeding tongs), but I unfortunately can't feed live (My roommate would raise hell), so I'm kind of dependant on f/t...

I really hope someone can help, I just want to do everything I can for her.