Ok, feed off the mice you do have and get her onto rats.

Also keep in mind length means nothing. I see you referring to her length. Try to get length out of your head and focus on appropriately sized meals on a consistent 7 day schedule for now.

Not trying to be rude, but this is all stuff you should know BEFORE bringing an animal home. Please do your snake a favor and do some independent research on the species as well as keeping them in captivity.