Did I ever tell you I used to think kissing causes a woman to get pregnant as a kid?
That's pretty funny!
I think we ought to end this conversation
Why do you want to end the conversation? Everyone thinks things like that as kids! There's nothing to be embarrassed about since we all think incorrect things from time to time, especially as children.
I'm not continuing
It's entirely up to you if you don't want to continue talking about this, but it's really no big deal. Nobody would judge you for this, and most people would actually just think it's a cute little anecdote! Don't be so harsh on how you thought as a child.