Little Children and Cursing

No one can stop you from cursing. The only person that controls what comes out of your mouth is you. You can curse whenever you want to, in front of anyone you want to. Most people that you will curse in front of will know the words that you're saying. Little children do not fall into that category.
You should make every effort to curb your mouth in front of little children (age seven or eight and below). At that age, most children don't know most curse words, especially not the Category Four words, and it's not your place to teach it to them. Parents are horrified when they hear their little children curse for the first time, and will do anything to make sure their children don't curse. It's completely inappropriate for you to teach a little kid bad words. If you will insist on cursing, then no one can stop you. Just try to watch your language whenever you're around little children.