How do I explain to my nine year old what sex is??

Is she too young??

I don;t think so, of course I have no experience. I don't think sex should be hidden like it is something bad. If she is asking then tell her. Of course you will want to edit the adult explanation. Try and remember what it was like to be 9.

theyre never too young to have some kind of answer. my 3 year old knows that sex is something private that only mommies and daddies do, and they have sex to make babies. as she gets older the explanation will get more in depth. for a 9 year old i wouldnt give them a graphic description or anything but its better they hear it from you then their friends.

yeah you have to!
but be blunt and simple

just say that sex is 2 people and they get close in a special way

Children are learning about sex very young these days. The media bombards them with it- and portrays it in a way that is not really truth (makes illicit sex look glamourous and passionate without mentioning the end results, for example) the music that some children are allowed to listen to is very suggestive, and therefore, they are hearing other kids talk about it at school, even if they are monitored at home by their parents about what they see and hear. If parents don't sit them down and explain it, they will learn about it from the wrong places in a negative way.

If you are a Christian, explain that sex is a beautiful gift that God created for a couple when they get married. Inside of marriage, it is a way for husband and wife to be close and show love to each other, and also was designed so that they can become mommy and daddy one day. Explain that God created it for married couples only, and that does not leave the opportunity open for her to think she is free to do it in the next couple of years or so when she starts thinking about boys. Now I know this advice is not going to be popular among many on this site, but please consider it anyway.