207. The usual time for the celebration of the sacraments of initiation is the Easter Vigil (see RCIA 23), at which preferably the bishop himself presides as celebrant, at least for the initiation of those who are fourteen years old or older (see RCIA 12). As indicated in the Roman Missal, “Easter Vigil,” the conferral of the sacraments follows the blessing of the water.
An interesting preference for the bishop to preside. Presumably that directive is for the cathedral parish, or for the bishop to travel to a catechumenate center or to invite the elect to the cathedral. Equally interesting is the bias for older teens and adults. Children may be baptized at other times, and by other ministers.
I’ve never been aware of a cathedral in which the bishop wouldn’t baptize younger children.