Who was the first black girl to go to a white school?

The answer to that question is lost to history. Although many, many, African-Americans came to the USA as slaves, many also came as free citizens. Although boys were much more likely to be enrolled in school than girls, there were still plenty of girls enrolled in schools. More than likely the first girl of African ancestry to enroll in school was enrolled in the 1600s although it is possible that one or more were enrolled in school in one of the colonies in the late 1500s.