There are many important sacred rites within the Catholic faith, and Confirmation is one of the more important ones. Children are baptized when they are still infants, and they have no choice in the matter of becoming Catholic. They are raised as members of the church, and the church contributes to their religious education as they age into teenagers and adults. While they consider themselves to be full Catholics, this does not truly occur until they confirm their choice to be Catholic.
When Catholic children become teenagers, they are expected to go through the rite of Confirmation. They take special classes to educate them in their adult roles in the church, and they are schooled in the actual ceremony. This ritual gives them the opportunity to declare they have accepted the religion that was chosen for them as infants. Before they are allowed to participate in the ritual, they are tested to ensure they understand they will become fully accepted members of the church with all the rights and responsibilities their parents enjoy.