A biography is to give account of events and significant moments and academic achievements of a person. An autobiography, instead of being written by a different author, is an own record of a life story written by the same author. A predominant characteristic of an autobiography is that it is written in the first-person point of view, accordingly the author has access to his or her own experiences and thoughts. It is important to add that the narration of events takes place in the first person mode.
You can tell because the passage states the thoughts/feelings of multiple characters, while not using "I" or "You" or any other first or second person pronouns.
