1st Holy Communion

What is First Communion? 
First Communion is considered one of the holiest and most important occasions in a Catholic person's life. It is the first time that a person receives the Sacrament of the Holy Eucharist, which is the eating of consecrated bread and drinking of consecrated wine. Catholics believe these to be the Body and Blood of Jesus Christ. Most Catholic children receive their First Communion when they're 7 or 8 years old, because this is considered the age of reason. Other people can receive communion for the first time whenever they've met all of the Catholic Church's requirements.

Preparation

For anyone to receive communion, that person must be considered to be in a state of grace. Traditionally, young Catholic children will make their first confession, also called the Sacrament of Penance, a week before receiving their First Communion. At confession, the child will tell his or her sins and misdeeds to a priest and receive a penance in exchange. The penance usually is several prayers to be recited immediately after leaving the confessional.
Confession isn't the only requirement for receiving the Sacrament of the Holy Eucharist; the Sacrament of Baptism must have been received as well. A child, or any person, who has not been baptized cannot receive communion. If the child has been baptized, he or she generally begins studying for First Communion in first grade. Catholic children who don't attend Catholic school go to religious instruction classes after school or on weekends.
On the day of one's First Communion, and whenever receiving communion thereafter, those who are partaking must fast — which means not eating any food — for at least one hour before receiving the sacrament. Drinking water or taking medicine, however, are exceptions. This type of fasting is called the Eucharistic Fast.

Meaning

A child's first communion is often a cause for celebration, but to many Catholics, the event has a deeper meaning. They believe that the event means that a child has studied and understood, to the best of his or her ability, what Catholics call the mystery of transubstantiation — the changing of the substance of ordinary bread and wine into the substance of Jesus Christ's body and blood, according to Catholic beliefs. Catholics believe that, before receiving communion, a child also should be able to tell the difference between Eucharistic bread and regular food.

Afterward

After First Communion, young Catholics must attend church every Sunday, and they are encouraged to receive communion frequently, even weekly. If one has missed Sunday mass without good reason or has committed a mortal sin, that person is expected to go to confession before receiving communion again. Most Catholics go to confession at least once a year, usually during Lent — a 40-day observance that typically begins in February or early March and ends in late March or April.