That was not my experience at all. My first confession covered a couple of VERY sinful decades since my baptism. The event we had during RCIA was great. We had prayers, sang some hymns, and the pastor spoke for a few minutes about the sacrament and the mercy of Christ. And then we went into lines for the multiple priests available.
My confession did not take too long, under 5 minutes. I had gone through an examination of conscience pretty thoroughly a couple times,so I was prepared. My particular sins were confessed along the lines of “I have take the Lord’s name in vain many, many times. I have lusted many many times. I have…” etc etc etc. With my list in hand, it did not take very long to list them off. At the end I mentioned to the priest also there were undoubtably many more sins that I had forgotten, but for these I was also very sorrowful and ashamed of, and was penitent over them.
The priest didn’t need to know the exact number of sins, since beginning with the confession, I mentioned at the beginning “Father, forgive me for I have sinned. This is my first confession, and it has been over 2 decades since my baptism.” He will understand what you mean by too many to count.
My confessions since are very quick. Number and kind, and get to the point. It’s not a counseling session, but instead a confession. The priest will give some words of encouragement and assistance, but it’s not meant to take very long.
Welcome home! I hope your experiences are similar to mine. The feeling you get coming out of the confessional is pure joy! KNOWING your sins are forgiven by God through the sacrament He created is awesome. And it means so much more to me since for the majority of my life I did not have it available to me in my denomination.