K.L.
My oldest daughter is 3 as well and we started around 2. I started early because i was molested as a child so i wanted to start really early to prevent anything from happening and i wanted her to know what a stranger was early, i wanted also her to know that she doesn't have to say hi or anything to some one she doesn't know. We started out by saying don't talk to anyone you dont know. it sounds simple and it is. Now she will tug on my leg and say, "look mom a stranger" and i say "yes, and what do we do?" she now says "we don't say anything to them we come and get mommy or daddy." Its the same thing with inappropriate touching. We have always told her that that was her "privates" and that no one was supposed to touch it except for her mommy,daddy, and grandma when we were washing her or wiping her. She says " Thats my privates," Hope this advise works for you!