The role of your sponsor is very ancient. It was introduced in the very earliest days of the Church. It is very important for you, together with your parents, to choose a really good Confirmation sponsor. The person chosen has always been a Catholic Christian, of good standing, who has lived his faith in an exemplary manner. So, it shouldn’t really be old, deep-pocketed Uncle Joe, who doesn’t have a clue about the faith but might well treat you to a gold watch…It doesn’t even have to be a relative of yours. It might possibly be a young adult who is involved in the Catholic Church and could be a model for you to follow. You see, your sponsor is not simply someone to accompany you on the day of your Confirmation. The cool outing and the nice big present are about as important for your Confirmation as the baubles on the Christmas tree are for Christmas–in other words, not at all. Though of course they’re nice, nonetheless. The job of your sponsor is above all to accompany you as you grow in your life and in your faith–in other words, a little bit like your own personal “coach”, given by a loving God.
In order to symbolize his acceptance of this duty before the whole community, your sponsor stands behind you at the moment of your Confirmation and places his right hand on your shoulder. In order to fulfill the formal requirements of the Church, sponsors must (a) be at least 16 years old, (b) have been baptized and confirmed, (c) live a life in accordance with the Catholic faith and appropriate to the duty they have taken on.
Ref: YOUCAT Confirmation Book (Bernhard Meuser & Nils Baer)