A 50-Year Memory: Coming of Age

Bar Mitzvah and Bat Mitzvah are Jewish coming of age rituals. According to Jewish law, when Jewish children reach 13 years of age. ...In addition to being considered responsible for their actions from a religious perspective, B'nai mitzvah may be counted towards a prayer quorum (Hebrew: Minyan) and may lead prayer and other religious services for the community. The age of B'nai Mitzvah was selected because it roughly coincides with physical puberty. Prior to a child reaching Bar or Bat Mitzvah, the child's parents hold the responsibility for the child's adherence to Jewish law and tradition. After this age, children bear their own responsibility for Jewish ritual law, tradition, and ethics and are privileged to participate in all areas of Jewish community life.

The Bar Mitzvah ceremony involves the young man or woman being called to read the Torah, a Haftarah portion, or both at a Shabbat or other service (Thursday morning, Monday morning or a festival) when the Torah is read, and it may also involve giving a d'var Torah, a discussion of that week's Torah portion.
--Wikipedia