As a child, when did you start cursing or saying things to your friends that you couldn’t say in front of your parents?

I know i cursed as a kid and did not very like it so i trained te be cursing free. That broke after like 10 to 12 jears after i got a friend that cursed a lot.
My mair reason why i did not like it was that if a mind reader exists i hope that at least i am not annoying. With the same motivation i structured how i think too, like less sentences that break halfway through.