Confirmation is a somewhat less widespread coming of age ritual that occurs when a child is 16 or 18. Confirmation was originally developed by the Reform movement, which scorned the idea that a 13 year old child was an adult (but see explanation below). They replaced bar and bat mitzvah with a confirmation ceremony at the age of 16 or 18. However, due to the overwhelming popularity of the bar or bat mitzvah, the Reform movement has revived the practice. I don’t know of any Reform synagogues that do not encourage the practice of bar and bat mitzvahs at age 13 today.
In some Conservative synagogues, however, the confirmation concept has been adopted as a way to continue a child’s Jewish education and involvement for a few more years.