Mary's sense of self or her self-esteem is being reflected in the passage. As a person develops their personality and undergoes socialization, a growing sense of who they are develops. This manifests into a self-esteem--how they feel about their personality and sense of self--which is the ability to understand who you are as a person.
The Americans most likely. It depends on what time you are talking about.
It is normal. My family used to do it back then and surprisingly it works. They usually have you wait until you don’t want it no more. Plenty of families do this, don’t worry not just yours !