Fake or not, most people have an experience (or in my case, 20 years of experiences) just like this in their lives; the ones that stop you from falling asleep at night years later.

We are human. We are fallible. No one remembers, other than you, and if they do they don't think about it nearly as much as you do.

You don't need to self-flagellate about a mistake years ago, for the rest of your life. If anything, use it as a marker for how much you have progressed and learned since then. You wouldn't make that mistake again, would you? It's a lesson, not an albatross.