The only thing I can suggest, is deconditioning. I had to handle mice and rats in my job; I used to be nervous about the really big, wise rats as well as mice. Trying to catch a mouse in a cage was really tricky for me, I found it easier to pick up a rat.
What worked for me, with my job - I used leather gauntlets at first (tricky with mice - they're so small). First we were told the correct way to do it, then shown the correct way, then we had a go. Once you know what you're doing, it's much easier to feel confident and safe.
So, a suggestion - take her to a pet shop, or a vet, and see if you can get her some exposure to the critters and, as SHE is ready, encourage her to get closer. Let her watch closely as someone else picks up a mouse and then puts it back down again. Show her that as a rule, mice will not bite you. It takes a lot of aggravation to get a rat or mouse to bite. With all the rats that I handled, I only ever got bitten once or twice and THEN only by particularly aggressive and irritable rats (they were hormonally imbalanced - long story). I never got bitten by one of those old, cunning rats that used to scare me the most.
Maybe all she will be able to do is watch the mice running around in their cage. Encourage her to watch, to see what they do and see how they behave with each other. Mice are not naturally aggressive and watching them interact socially may make her feel less afraid of them.
Marg
