That black thing doesn't qualify as a hide- it's way too open. You want something like this (below) with a lower ceiling, & only one door that is slightly bigger than the snake's body.
https://www.reptilebasics.com/hide-boxes https://www.reptilebasics.com/medium-hide-box You want a hide that's a little bigger than the snake's coiled body, but if you get one that's much larger, you can also make it "cozier" for them by crumpling up some paper to wad into one end- & so you don't need to buy new hides constantly while your snake's grow.
These (from Reptile Basics) work great & come in many sizes, but similar ones are available by other brands too, or for the time being, even cardboard boxes of the right size & a doorway cut can work just fine, though when they get dirty, you obviously cannot clean cardboard, so they're disposable rather than washable.
Hides are very important for a snake's sense of security. Get this right before you try feeding again, okay?
What size mouse??? Eyes open or closed? It matters because mice (or rats) with eyes open DO BITE BACK in self-defense, & should only be offered with close supervision. Even then, if it's a hopper with eyes open for longer than a day, they can hurt your snake faster than you can intervene, so just be aware & make sure your snake is really ready to eat (ready to make a kill) before putting in an active hopper mouse.
And from the age & size of your snake, I'd assume it's on hopper mice- most hatchling BPs are big enough to take hoppers so many are started on them. FYI, never leave them in with your snake overnight, if your snake doesn't take it while you're watching, take the mouse out before you leave or sleep, etc.
(Hoppers are weaned, eating on their own, very active, eyes open, about half the size of mature adult mice.)
Another thing to consider (for helping a new snake relax & feel "at home") is to make their new home very similar to how they were kept by the breeder. If you didn't see that in person, you can always ask. Many new owners understandably want to provide space that a new snake just isn't ready for. Many breeders use racks with more privacy, & not a lot of space or furnishings. At this point though, while it would help to ask & to know, you don't want to keep making changes with this new snake already home with you- the time to make changes would have been prior to bringing her home. For now, it would help to know, so you understand why she's not wanting to eat yet.