Nansai desu ka is a commonly asked question by Japanese people when you first meet them. It is not considered a rude question, as it is in American culture.
Japanese people are very curious about the age of a person.
Omedetoo-gozaimasu can be used almost any time when there is a happy occasion such as a wedding, New Year, a graduation, and so forth. Chichi and Haha are used when referring to your own parents.