Many times when you get them from breeders they're kept on a leaner diet. Your girl looks a bit thin but she'll bulk up fast once she's on a more growth oriented feeding regiment. She can most likely handle a rat pup now but it's fine to start her on fuzzys if you're more comfortable with those. I use the 10-15% of body weight feeding method as a more of a guideline than a rule. My younger or smaller snakes sometimes get a bit more food. I feed them every 5-7 days for the first year then I scale it back to weekly feedings. My adults eat every 10-14 days.