My mother became a US citizen when I was 17 and I did live with her but not sure about the being listed and why it should matter as I was a minor as my ex just became a citizen and the judge told her that if her parents were citizens before her 18th birthday she would not have to done this later in life. True?

For minor under 16, it should be automatic but unfortunately, many people did not mention in form N-400 that they have children.

When were you born? The rules have changed over the years.

It is true that under the Child Citizenship Act of 2000, if a parent naturalizes before you're 18, and you were a permanent resident living with them, you automatically become a citizen. If you were born before 1983, the rules are slightly different -- both parents have to naturalize before you turn 18. etc.