The story is told by an unnamed narrator in the third person; however, the narrator has special access to Kit’s thoughts, feelings, and consciousness. This is what is meant by “third person limited” (or "close"): the narration is written in third person, yet the narrator is mostly limited to Kit's perspective. An example of third person limited narration is as follows:
“I had a black nursemaid. But I never needed anyone but Grandfather. He was –” There were no words to explain Grandfather. (2.22)
Kit describes her relationship to her father, but the narrator already knows her deepest feelings on the matter and completes her sentences for her.