Hi there!
Do you have a current weight on her?
Sounds to me like she's being quite underfed, especially for that length. My girl is 6 months, and last length a week ago was 17"... She eats about 10-15 supers in one sitting. Depending on the day, she'll get fed a 2nd or 3rd time, usually with a different worm. My 4 month male also eats quite a bit...smaller supers, and more soft-bodied worms, but still a lot of protein.
Always keep greens available, but you may want to start trying to feed her more often, and make sure it's dusted with Calcium w/ D3. If she's picky on supers, try Dubia's, BSFL, and some treat worms like butterworms, and hornworms.
Try to feed more, and keep track of her weight every few days.