To preface this, I'm not a prude, or a hypocrite, and I love a good swear, at work, at home but not necessarily in earshot of the children, and when I'm out with like minded friends.
My parents never swore very badly in front of us as children, bloody was probably the worst. But that didn't stop me from knowing what all the swear words were, and I did start to use them more at primary school towards the end of top juniors as it was then, but telling a boy to "fuck off you wanker" during a game of tag and getting overheard by a dinner lady and being sent to the head was as bad as it got. I did swear a bit more amongst my friends but didn't get heard,most common words were shit, fuck and piss I think, never cunt. Once I got to high school, then it was a bit like a switch had been flicked, and although I would still never dare to swear at a teacher or my parents, I would find myself swearing more loudly in conversations with friends at school, I remember first calling another girl a "stupid cunt" in Y8 as we had a fight over some stupid diary thing.
The point being that now I have children I do make comparisons between myself at their age and how they behave and talk. With 2 already at high school, one about to start in Sept and another at primary still, is there still a distinction between what's acceptable at each stage? I hope that there is, although I do realise that I don't necessarily know everything that goes on in my childrens' lives. I'm pretty certain that youngest DD(8) doesn't swear at all; DD(11) I'm pretty certain has said words like shit, and maybe fuck in the context of an annoyed "fuck off" to someone pissing her off. Eldest DD's (12) and (14) I know are quite sweary with their friends and in text conversations.