That's not how being mixed race works.
Double points for being half black.
Triple multiplier for being mixed black in America.
Mixed racial kids never really fit in any culture that isn't already a heavy genetic mixed pot already.
Most of the time when you mix races you tend to look mixed race, but black people are a large group of different strong racial traits, really (dark skin, hair, facial structures) and half black kids always look black to outsiders.
Being American she also is pretty much guaranteed to think of her self as "light skinned black".