Congratulations! Whether you are an adult studying for your own Baptism or you are preparing for the Baptism of your child, you take an extremely important step in you and your family's spiritual life. Baptism is necessary for salvation. Our Lord Jesus Christ instituted Baptism as the means of removing original sin from our souls, of being born again and incorporated into His Mystical Body, and of becoming members of His Church. There is nothing else more important for you right now than to ensure that you and your family members are baptized.
Children who have reached the age of reason, which is generally around 11 years of age, can no longer be baptized as infants. The Rite of Baptism is the same for everyone, but the process differs slightly. These children, since they have the knowledge of right and wrong, must generally take an RCIC (The Rite of Christian Initiation of Children) class to understand what the Church teaches.
Adults who have not yet received the Sacrament of Baptism must go through instruction in the Catholic Faith in order to receive Baptism. This will often take the form of RCIA (The Rite of Christian Initiation of Adults). These classes ordinarily begin around September of each year and end at the Easter Vigil when the adult is baptized, receives our Lord's true Body and Blood in Holy Communion, and receives the Sacrament of Confirmation.
All baptisms (infant, older child, or adult) require a godparent. Being a godparent is both a great honor and a serious responsibility. For that reason, the Church has put several laws in place regarding who may rightfully serve as a godparent.