Thanks for all the great responses. I hope you don’t mind if I add another question:
This is a scenario. Murder for this question is the same as “x” in a math problem.
Me: “I murdered people, both before and after I knew it was a sin, which was about three months ago.”
Father grants absolution.
Several months intervene. I commit more murders. I eventually go to Confession. At this Confession, I confess in something like the following way: "In between time x and time y, I murdered habitually (I confess this several more times, with slightly varying numbers/terms, depending on what I think is accurate, to make sure the number is correct). Then, around a year from the time I was cured of my habit of murder:
Me: “Oh no! I didn’t number the murders correctly at the first Confession, and now that I think about it, I knew murder was a sin a year beforehand!”
Now that I think about it, I may have confessed the murders from my whole life to the priest, but I am unsure.
I hope this wasn’t too confusing (I realize that my writing is often all over the place), and I beg you to analyze it and tell me what needs to be done. I can provide extra information if that helps. Thanks!