Happy new year, and new birth of a life seeking faith and grace.
There are people who have something called scruples, it’s sort of a spiritual Obsessive Compulsive Disease. We sometimes carry with us a feeling of guilt over things we’ve done in the past. But we need to remember when a priest absoves us from the sins we have confessed, and any we may have honestly forgotten they are forgiven in the Name of Christ, who authorized the priest to do so in His name. The Sacraments, while dispensed by priests are works of Christ. Jesus empowers the graces we recieve in the Sacraments, they are not done simply by the priest, but by the priest through Jesus’ very self.
Having been baptized a Catholic or recieved into the Church at an earier date, one would not have to go through RCIA, but many parishes do offer it to those returning to the Church so they can understand and learn the Faith more fully. The course you have started will give you the same information, and may fit your schedule more easily.
You remain in my poor prayers.