The sacrament of confirmation is one of three which initiate people into the Catholic Christian life. The three sacraments are Baptism, Confirmation and reception of the Eucharist. Someone, then, who is not confirmed, is not fully initiated sacramentally into the Christian life. It is for this reason, that people wanting to receive the sacrament of Holy Matrimony, need to be confirmed (as well as baptized, of course).
Confirmation can be received at any age. The normal procedure is for an adult to be baptized, confirmed and receive Eucharist at their initiation at the Easter vigil. Technically, the baptism and confirmation should not be separated by large space of time. In the Western ecclesial tradition, we tend to do this, to assure that the link with the bishop is made clear, when young adults are confirmed at the age of 12 or 13.
Adults wishing to be confirmed need to contact our parish, and join the RCIA program. This program is the initiation of adults into the Catholic life.
Young adults, below the age of 16 need to contact our catechism leaders, and join in the faith education programs of the young.
The grace of confirmation, which completes the baptismal initiation into the life of Jesus, is one which makes us mission minded children of God. If by baptism, we become a child of God, in confirmation, we take on a deeper calling to be 'doing the works of God'. A confirmed Christian has a serious obligation, both through acts of charity, service and through conversation, to spread the Good News of the Gospel.