Bar, and Bat Mitzvah.

The concept of Bar Mitzvah is at the age of 13, for boys.The boys take responsibility at this age for their sins, and start to wear the Teffilin(Some wear it about a month before, or so). The Children have all the same commandments as any 30, or 40 year old. The only thing is, kids from the age of 13-20 are not responsible for the punishment of Karet. This Mitzvah was passed down to Moshe at Har Sinai. The custom of Jews all around the world, is for the Bar Mitzvah boy to read the Torah the week of his Bar Mitzvah. The date of the Bar Mitzvah is the child's Hebrew birthday. The concept of Bat Mitzvah is for girls at the age of 12. The reason for girls, 1 year before boys is because girls mature faster than boys.