I would definitely try feeding in her enclosure. I've had success with that. If she's small, a 20G is quite large. Try "cluttering" it up with some fake vegetation or even crumpled newspaper so she feels like she's hidden.
If you're dangling it, I'd try getting some tongs and grasping the rat at the nape of the neck and "dancing" it sort've in front of her. I was using the dangle-by-the-tail method until recently and have noticed mine have been striking quicker when the rat's in a more "rat-like" position (aka on all fours).
If you're using rats, try mice and vice versa.
You could also try leaving it in front of her hide (like in the doorway) overnight. I've had success with this. If I don't get a strike I leave them for about an hour, but then they get fed off to someone else (I really hate to waste).
Whatever you do, don't try gerbils or hamsters...I've heard this is like crack to balls and once you get them on, you can't get them back off. And gerbils and hamsters are expensive.
If you're still having trouble, try live.
Also, don't handle her at all until she's feeding regularly. Like seriously. Nothing but water changes and spot-cleaning. And I wouldn't offer more than once every 5 days. Preferably once a week until she starts eating regularly.
I know this was kinda rambly but this ^^ is the extent of my advice on how to get these silly snakes to eat! LOL