Beautifull snake! She doesn't look bad but she could definitely use some more weight. I would not switch her to rats just yet though. At this time of year there is a good chance that she will stop eating in the next month or two and refuse to eat until spring. I have a male that goes off of feed for six months every year. One of my other snakes eats sporadically this time of year. Since you don't know her habits yet I would go with what she is used to so as to insure that she gets as much nutrition as possible rather than stressing her out. It may not even be possible to get a snake that age to switch. All the balls I have switched were under a year old. The best bet would be for you to stock up on XL mice. I have an adult male that is 5 years old, 4 1/2 feet long and weighs 1975 grams on empty that eats 2-3 XL mice every seven days (same snake that goes six months). The XLs can usually only be gotten with any reliability at expos and off the internet so if you don't have a freezer you can put them in you may want to breed a few. If she goes off of feed, the easiest time to get her to switch is the first meal she takes. Try an unscented med rat. If she doesn't want it try scenting with a mouse or mouse bedding. If this doesn't work, you can try chicken broth. This is all under the ussumption that you are feeding FT or PK though. If you are feeding live you will have to get tips from someone else because I start mine on FT right out of the egg and really don't have experience with switching live feeders. Good luck!