I spent alot of time in the garage helping my dad. I learned "fuck" and a few others at an early age.
Then I married a redneck bartender and my vocabulary widened even more.
My son's 13...ever heard a group of 13 year old boys when no adults are in earshot?
(13 yr old girls aren't much better, or at least I wasn't) It was harder when he was younger I'll admit.
I really don't believe in "bad" words, I think a word is only really bad if it makes a person feel bad by saying it...and then it's not the word, it's the person using it and "how" they used it.
I don't make a fuss about it, my rules are...try not to use it out in public because it does make people think less of you sometimes and I'm not dealing with phone calls from alarmed parents and shocked neighbors, don't use it at your girlfriends unless you don't want invited back, and if you slip and say it at school they'll give you detention...so that is on you...mom will NOT bail you out.
If you're going to cuss, cuss responsibly and in moderation.