1. Yes, but it is easily avoidable. Feed your snake one appropriately sized rodent once a week. Appropriately sized is a rodent about the same or slightly larger than the fattest part of your ball python. Just eyeball it. Since you have a baby if you'd like you can feed your snake every 4-5 days until she reaches 500grams or so and is no longer a baby. This isnt necessary but does usually make them grow faster.
2. Read above^. Whether you choose a 4-5 day or 7 day schedule is entirely up to you.
3. You dont HAVE to switch them over to rats if you dont want to. The main reason people usually do is because its more convenient to feed 1 f/t rat than multiple f/t mice. You can switch them over whenever you want. Some breeders start their bps on fuzzy rats right away so your girl could probably take them now.