The first and most important answer to this question is – they already have!
You, as the parent, are referred to in all Church documents as the “primary educator” of your child(ren). By now you are surely aware that children are the great imitators of life (both the good and the bad). Prayers at the table and at bedtime will teach children to pray. Gestures of forgiveness in the family will teach them about the forgiveness of God. Bless them and they will learn that life is grace filled.
Parish programs are designed to help you in this most important task. Most parishes have programs that start for children around the age of 4 or 5. All parishes are expected to have pre-school programs of some type when it is possible to do so. Many parishes have a program called “Liturgy of the Word for Children.” This program will take children out of the Sunday Mass so that they can hear the readings for each week in a language more appropriate to their understanding.
Children should be enrolled in the religious education program at least by first grade. This is important since many parishes have a two year enrollment requirement for the reception of First Penance which normally happens in the second grade. Parishes will usually have formation programs for children and youth through Confirmation in the 11th grade and beyond.