These are pretty small snakes at a year old- I can't imagine feeding one a weaned rat, so I'm guessing you fed her too much (ie. it was too big for her to handle). Also, I'd make sure that her warm area is a good 90*.
Right now, because she regurgitated her meal, she needs at LEAST 2-3 weeks without food to allow enough time to replenish her digestive enzymes. When you DO offer her food again, it must be very small- I assume she has never eaten for you before? It's odd that she'd be on rats, but if that's the case (& she really won't eat mice at all?) you'll want to be feeding her pinky rats or very young fuzzy rats (eyes CLOSED) when you offer her food (& feed her small meals for quite a while while she recovers). Weaned rats are way too big for this snake, IMO.
FYI- I have an adult Spotted python (now 14 years old)- & I've had her for 13 years, since she was a yearling. She's never eaten anything but mice of the appropriate size- & she prefers pre-killed (fresh or f/t). I would NOT feed MY spotted python a weaned rat, & she's an adult snake, nearly 4' long. She eats one or 2 small adult mice (hoppers) per meal.
Another possibility is that you failed to completely THAW the rodent- If you feed a rodent that is still frozen inside, your snake WILL barf it up. How do you thaw your rodents?
And: https://ball-pythons.net/forums/show...-Post-Pictures Please include something for size reference, like a ruler, etc.