In Judaism, the traditional age for a girl’s bat mitzvah in many communities is 12.
Bat mitzvah means “daughter of commandment.” In traditional Jewish law, girls reach religious maturity earlier than boys, so a girl generally becomes obligated in Jewish commandments at 12, while a boy traditionally reaches that status at 13.
The practices surrounding bat mitzvah vary widely. In many Orthodox communities, a girl may mark the occasion with a speech, study session, celebration, or other event, while public Torah reading and leading parts of the service depend on community practice. Conservative and Reform communities commonly include public ceremonies modeled on bar mitzvah celebrations.
The modern bat mitzvah became especially visible in the twentieth century. Judith Kaplan, daughter of Rabbi Mordecai Kaplan, is widely recognized as the first girl to have a bat mitzvah ceremony in the United States, in 1922. Earlier and later communities developed their own customs, so no single format applies everywhere.