Already, at a very young age, this girl is being molded into her female role. She is dressing up in her mother's high heels and practicing her feminine mannerisms. She is carefully examining herself in the mirror and seems content with the future self that is being reflected back to her. The mirror is obviously meant just for her because it is so short. We can assume that while this young girl is looking in the mirror, her brother is outside playing in the mud.
Young girls are prepared to be the objects of the male gaze from a very early time in their lives.