"With Baptism and the Eucharist, the Sacrament of Confirmation constitutes the whole of the "sacraments of Christian initiation"... It is therefore necessary to explain to the faithful that the reception of this sacrament is necessary for the fulness of baptismal grace."
(Catechism of the Catholic Church 1285)
To register your child for the sacrament of Confirmation, you must do so when they begin grade 8th.