I offered her the rat again but this time I kept her in the cage. She nailed it after like 45 seconds. I guess she just really likes to stay at home. I'm glad not all of my snakes are as picky as her. Whatever, I'm just glad she's eating!
I also think the breeder must be confused one which snake he sold me lol. Mice are definitely too small for her.
Thanks for your help btw. [: