You could say that Bird is right about the expectations placed on Snow considering the way in which Snow’s father lavishes her with gifts and attention. You could put forth the argument that Snow is rather spoiled and entitled. In the story, Snow is depicted as an enchanting figure and wants for little. At one point, Boy declares, “Everybody adored Snow.” In a sense, Snow isn’t expected to do anything: she can just, more or less, be.
Yet such adoration has its drawbacks. You could argue Bird is downplaying the pressure put on Snow. You could say that her light skin color and the way in which it allows the Whitmans to pass themselves off as a non-marginalized ethnicity places a great deal of expectations on her. You could argue there’s an undue burden on Snow to continue the lie created by the Whitmans.
Additionally, you could argue that the exceptions aren’t so much a result of Snow’s own thinking as they are a result of her stepmother's. You could make the argument that Boy expects odious things from her stepdaughter, which is why she sends her away. Remember, Boy does not treat Snow kindly. She confesses to wanting to hit or slap Snow. In the context of her relationship with Boy, you could argue that Snow’s light skin transforms her into the marginalized one. You could reason that Boy has nefarious expectations of Snow because of her skin color.