please I need help with THE TALK

China

so I had my planned on having THE TALK with my 6 year old daughter next year because my mom started at 8 and so I figured that give my daughter a year to prepare just in case she did start at 8 like my mom. well her father and i are not together and her step dad (was with for 2 years so she called him dad) and i are also not together anymore but have a son together. her father has married and had 7 yr old step daughter and her step dad has 7 yr old and 6 year old step daughters and a 2 yr old step son. well her step dad's woman and i talk and decided when we have THE TALK we will do so with our three girls because they are all close and we don't want to tell one then that one child go and tell the others. well my sister is pregnant with baby #3 and her oldest (5 yrs) asked my daughter how people got pregnant well she told her what her step sister (her father's step daughter) had told her that when you eat eggs they go to your belly and hatch into babies. I'm sorry but that is not how I want my daughter to know this and now we are go ing to have to have THE TALK before we wanted to. who else things this is ridiculous was to tell a child about baboes? And the age??!!! I'm not sure how to correct this...