A. The narrator had first regarded natives as naturally inferior, born to serve, and bound to their duty towards the white "baas" or boss, that is, her father and his family. Later, she learns that those natives are people with their own history and claim to the land they had owned and lost to the white settlers. She develops a certain kind of understanding and respect for them, although she is too young (14 years) to articulate it in a precise manner.
B. She never explicitly says that her relationship with her father was affected by these findings, but it is apparent she has come to question her parents' racist attitudes after she met Chief Mshlanga. Near the end of the story, when she recounts the incident with the goats, the reader can feel her attitude by the details she notices: her father's triumphant look, the Chief's silence, and helplessness. She is just an observer, but we get the feeling she will grow up to be a different kind of person than her parents had taught her to be.
C. By reading the books about Chief Mshlanga's influence and authority within his tribe, she gains a new perspective about the natives and about Africa itself. She realizes that it may have been her country, but it doesn't mean it is only hers. On the contrary, it belongs to the people who have lived there for centuries. That is why she feels fear for the first time when she steps on Chief's territory after reading those books.