Why do you need to be confirmed?

In the Anglican Church, a person's faith is confirmed (by the bishop) as a reason of the assignment the god-parents of that person made on the of baptism (given that he was young and unable to tell whether he will be a Christian or not) .A person at the age of understanding, usually 12 and above confirms his Christianity and the god-parents are no longer under the task of caring about his Christian faith. However, this is not biblical-mandated and has therefore faced criticisms from the other sects of Christians.(Proverbs 22:26)The case is the same for Catholics. It s argued that according to The Bible one must accept Christ personally."For with the heart man believes unto righteousness; and with the mouth confession is made unto salvation"Romans10:10.