Some snakes have had bad experiences with live food and maybe that's why she was hesitant to take the prey- "too much motion". Snakes have personal preferences.
Whatever you do, don't try to rush putting weight on her. Feeding too much or too soon will overwhelm her digestion & she might hurl it, which would make things
worse as you'd have to wait longer until her digestive enzymes get replaced (otherwise she'd hurl the next meal too, if fed too soon). Most snakes act like they want
more after eating...just learn to ignore that pathetic look.I'd feed her about once a week for now & one item per meal, as long as she is digesting well etc.
(and pinks are the wrong food for her anyway, fuzzies are what's best att)
BTW, the substrate you're using looks great but it's better to use white paper towels at first with new snakes, while you make sure they don't have mites. Do watch for
that (tiny specks moving, on snake or often in water bowl)...especially since she's already skinny, a mite population explosion could kill her. (seriously)
But with your "TLC" she'll hopefully thrive...We look forward to seeing that almost as much as you do.