The Roman Catechism adds this: “At what age children are to receive the Holy Mysteries no one can better judge than their father and the priest who is their confessor. For it is their duty to ascertain by questioning the children whether they have any understanding of this admirable Sacrament and if they have any desire for it.”
From all this it is clear that the age of discretion for receiving Holy Communion is that at which the child knows the difference between the Eucharistic Bread and ordinary, material bread, and can therefore approach the altar with proper devotion. Perfect knowledge of the things of faith, therefore, is not required, for an elementary knowledge suffices-some knowledge (aliqua cognitio); similarly full use of reason is not required, for a certain beginning of the use of reason, that is, some use of reason (aliqualis usus rationis) suffices.
To postpone Communion, therefore, until later and to insist on a more mature age for its reception must be absolutely discouraged, and indeed such practice was condemned more than once by the Holy See. (St.Pius X, Quam Singulari)
By Jose Gallegos y Arnosa
First Communion attended by Konrad Adenauer