The reformed understanding of Confirmation is this:
by the sacrament of Confirmation, [the baptized] are more perfectly bound to the Church and are enriched with a special strength of the Holy Spirit. Hence they are, as true witnesses of Christ, more strictly obliged to spread and defend the faith by word and deed. (source)The traditional understanding of Confirmation is very similar. The Council of Trent says:
A sacrament in which the Holy Ghost is given to those already baptized in order to make them strong and perfect Christians and soldiers of Jesus Christ.
It has been variously designated: bebaiosis or confirmatio, a making fast or sure; teleiosis orconsummatio, a perfecting or completing, as expressing its relation to baptism. With reference to its effect it is the "Sacrament of the Holy Ghost", the "Sacrament of the Seal" (signaculum, sigillum, sphragis). From the external rite it is known as the "imposition of hands" (epithesis cheiron), or as "anointing with chrism" (unctio, chrismatio, chrisma, myron). The names at present in use are, for the Western Church, confirmatio, and for the Greek, to myron. (source)
St. Thomas says about Confirmation that Confirmation is to baptism what growth is to generation. Now it is clear that a man cannot advance to a perfect age unless he has first been born; in like manner, unless he has first been baptized he cannot receive the Sacrament of Confirmation (Summa Theologiæ III.72.6). This notion of Confirming has nothing to do with making one an adult, but rather has everything to do with making one perfect in his baptism.
As we think of the Sacraments of initiation, we should be thinking not of age, but rather of perfection. If baptism wipes away original sin and Confirmation perfects that Sacrament, then why should we have an expectation of waiting until one is nearly an adult? Wouldn't it be better served to see the perfection of baptism come as soon as possible? The Catechism of the Council of Trent continues:
Those receiving Confirmation should also be in the state of grace; for the Holy Ghost is not given for the purpose of taking away sin but of conferring additional grace. This condition, however, refers only to lawful reception; the sacrament is validly received even by those in mortal sin. In the early ages of the Church,confirmation was part of the rite of initiation, and consequently was administered immediately after baptism. When, however, baptism came to be conferred by simple priests, the two ceremonies were separated in the Western Church. Further, when infant baptism became customary, confirmation was not administered until the child had attained the use of reason. This is the present practice, though there is considerable latitude as to the precise age. The Catechism of the Council of Trent says that the sacrament can be administered to all persons after baptism, but that this is not expedient before the use of reason; and adds that it is most fitting that the sacrament be deferred until the child is seven years old, "for Confirmation has not been instituted as necessary for salvation, but that by virtue thereof we might be found well armed and prepared when called upon to fight for the faith of Christ, and for this kind of conflict no one will consider children, who are still without the use of reason, to be qualified." (Pt. II, ch. iii, 18.)
So, the idea of Confirmation as soon as baptism moved from the realm of immediately after baptism until such time as reason was employed. However, there still is no mention of the idea that it makes one more mature in his faith, but rather that he is perfected. As time passed, and as bishops became fewer and fewer, the Sacrament was moved to a later time.
In today's world though, fighting the battles we are fighting with regard to Catholicism, shouldn't we be arming the faithful with as many spiritual weapons as possible? Doesn't it make sense that if Confirmation be a way of perfection or perfecting Baptism, then shouldn't that be administered sooner than 15 or 16? It is my contention that if one can use reason, then one should be confirmed. Since there is no "fast age," we shouldn't be waiting, we should be promoting the quicker and more expedient way of initiating Catholics into the fullness of the Church.
As late as 1897, Pope Leo XIII comments to the Bishop of Marseilles, commends most heartily the practice of confirming children before their first communion as being more in accord with the ancient usage of the Church. I think that we should be imploring our bishops to follow the lead of His Holiness and call for a return to a younger age of Confirmation. If we are to strive for perfection, then why shouldn't we be promoting it's implementation as soon as possible?