My 13 year old is difficult to talk to about sex at all, but I do believe that we have made great progress over this visit so far. She finally knows what all of her lady parts are actually called now, and I explained that anytime anyone does anything she feels uncomfortable with to immediately tell myself or her grandparents. I also found out that she kissed a boy last year, she was scared she got pregnant from a kiss...
My youngest at 3 can already name all her lady parts, and knows that she doesn't have a penis but a boy does. She also screams bloody murder if someone gets close to her vagina, even to wipe, unless it is me, my mom, or my sister.