Infants, who are not in danger of death, are licitly baptized in the Catholic Church only when there is a well-founded hope that they will be raised in the Catholic faith by their parents or guardians, which, by the way, includes a personal acceptance of Jesus Christ as Lord and Savior. (See links, below)
The Catholic parents or guardians of baptized infants are expected to evangelize them and encourage them to personally accept Jesus Christ as their Lord and Savior. Because Catholics expect baptized people to be believers, post-baptismal acceptance of the Lordship of Jesus Christ is typically not given a special liturgical celebration all its own. Though such an event is certainly a cause for celebration.
Unfortunately, baptized children are sometimes not raised in the Catholic faith. When such baptized-but-yet-unbelieving persons are enrolled in Catholic religious education classes designed to prepare believers to receive the other non-repeatable sacraments, such as Confirmation, or the repeatable sacraments for the first time, such as Reconciliation (Confession or Penance) and the Eucharist (Holy Communion), those preparing them are also expected to evangelize them and encourage them to personally accept Jesus as their Lord and Savior. Another poster has mentioned that candidates for Confirmation renew their baptismal promises.
In addition, at every Sunday Mass throughout the year, Catholics are given the opportunity to personally and publicly profess Jesus Christ as their Lord and Savior, using the words of the Nicene Creed, which includes the phrase, “I believe in one Lord, Jesus Christ.” Alternately, annually at Easter Sunday Mass, Catholics are given the opportunity to personally and publicly renew their baptismal promises — whether they made those promises themselves when they were baptized or because of their young age their parents or guardians spoke for them. During the renewal of baptismal promises, Catholics are asked, among other things, “Do you believe in Jesus Christ, His only Son, our Lord…?” And they are expected to respond, “I do.”
We all come into this world suffering the eternal consequences of Adam and Eve’s Original Sin; on account of Original Sin, we come into this world spiritually estranged from God. Unless we are reconciled to God before death, we are destined for Hell. Likewise, our own mortal sins cause us to be estranged from God. A participation in Jesus Christ’s sacrificial death on the Cross for the forgiveness of sins is the only thing that can reconcile us to God, save us from Hell, and gain for us eternal life. The sacraments of Baptism, Reconciliation, Eucharist, and Anointing of the Sick are, each in their own way, participations in Jesus Christ’s sacrificial death for the forgiveness of sins.
Regardless of age, when a person receives Baptism, he is reconciled to God through Jesus Christ and he receives the indwelling of the Holy Spirit, whether he is an infant who is estranged from God due to Original Sin only or he has reached the age of personal accountability and is also estranged from God due to his own past mortal sins.
Because Baptism can be received only once, as Sacred Scripture says, “There is … one Baptism…,” if a person commits mortal sin after receiving Baptism, he again becomes estranged from God and, unless he is again reconciled to God before death, he is destined for Hell. However, if he repents, he can be reconciled again to God through Jesus Christ by receiving the Sacrament of Reconciliation, also called Confession or Penance. In the Sacrament of Reconciliation, a baptized person confesses his mortal sins to God and to a Catholic priest, he expresses his sorrow for those sins to God and to the priest, and also expresses his firm purpose of amendment. If the priest thinks he has made a good and sincere confession, the priest absolves him of his sins in Jesus’ name, i.e., in the name of the Father, and of the Son and of the Holy Spirit. The priest also typically assigns him an appropriate penance to help him ameliorate the temporal consequences of his sin and to help him advance in holiness.
Pope John Paul II’s 1990 encyclical, On The Permanent Validity Of The Church’s Missionary Mandate, section 46, says, “Conversion means accepting, by a personal decision, the saving sovereignty of Christ and becoming his disciple. The Church calls all people to this conversion…”
Pope John Paul II’s Apostolic Exhortation On Catechesis In Our Time, section 19, laments the fact that sometimes people baptized as infants grow up “without any explicit personal attachment to Jesus Christ” and without “committing their whole lives to Jesus Christ.”