The main thing that sets this ceremony apart from the others, in my opinion, is that it is the last age ceremony ever. There is no longer any acknowledgement of age after the Ceremony of the Twelves. Once you pass this age, you are an adult.
The other thing that goes along with that is the fact that this is the ceremony where people get assigned to their jobs. So that makes it perhaps the most important ceremony of them all.
For these two reasons, the Ceremony of Twelve is different and more important than the other ceremonies.
the Ceremony of Twelve is special. It is when the Twelves are assigned/given a job or career, showing full independence. Their job is their first step in lives of being an adult. Apart from the other ceremonies, it is different because a job shows you are mature enough to step forward as an older person, an adult.
In that community it was so important about the ceremony of twelves coz only at the age of twelves they celebrate thier ceremony