A childhood belief about church

I did not come from a religious family, so I had no religious studies. I was also Canadian, so I didn't know what the amendments were, but had heard them mentioned a lot.

I always thought the commandments and the amendments were the same thing. So when someone said, "I plead the fifth" I figured they were talking about not stealing.
I never said anything, so was never corrected, and believed this up until teenagehood.