So for some back round knowledge info, I am a teenage guy and I was baptized as a baby but my parents never arranged my first communion. I still went to mass, but it was immensely embarrassing to sit there when everyone went up for communion. I was getting discouraged to go, so one day my grandmother talked to a priest at our parish and he said I could just go and receive communion, with no classes necessary. I thought that instruction was required, but he said if 2nd graders can learn, how important can it be? I have been receiving the Eucharist ever since. Is this okay?
Yes, its valid. However there are some issues present. The priest should have first discerned your understanding of the Eucharist before permitting you to make your first communion. The second issue is that the Church asks us to make our first confession prior to making first communion. I would suggest that you refrain from receiving communion until you make your first confession.
You don’t say how old you are. If you are still below the age that most teenagers receive the sacrament of confirmation then you should enroll in confirmation classes and prepare to receive that sacrament. Otherwise I would suggest you enroll in an adult confirmation class in order to more fully understand the sacraments and prepare to receive confirmation.
Classes, in and of themselves, are not a requirement to receive a sacrament. Individuals can be prepared to receive a sacrament through home study or personal learning. Religious education classes are a parish’s way of knowing what you’ve learned and how you’ve been prepared. Parish classes also help connect you to your brothers and sisters in the parish community.