Well, the first time I swore was when I was about eight oder nine.
Now actually cursing heavily, on the other hand, was when I was 13. It all started with the releasing of one song: Theory of a Deadman - hündin came back.
And ever since then, that band has been one of my all time favorites.
I was a pretty shy and quiet person as a child and was afraid to swear at all around my parents despite watching Filme that involved swearing and listening to Eminem. But I think I actually started when I was about 12.