That’s exactly what Deja Vu is. You’re convinced you know what is going to happen because you’ve seen it before. And when it happens you’re think, “I knew that was going to happen, it happened exactly as I had seen it!” So you remember it that way.

But in the moment you wouldn’t have actually been able to say what was about to happen. Your brain confirms that you did know what was going to happen when it does, because it’s essentially “reading” the memory as it “writes” it.

It helps that our conscious experience of the world is lagged a few milliseconds behind our instinctual reactions. So you actually did see it before you processed it happening, just by fractions of a second.

(NB: I am not a doctor or a psychologist or anything, this is just based on my experience and on what I’ve read. Human memory is very very flawed and we’re prone to remembering things differently than they happened, and be extremely confident about that misremembering. Especially the more times we go over that memory, rewriting it every time.)