Ask her pediatrician first off. Then search on google or whatever u use just the words u typed here and all will be answered. But I can help a little. Ok if u want ur daughter to just tell u when things are happening INFORM her about her body's up coming wonderful changes and what the changes will mean when she is an adult and is ready to start a family. This is going to be the best way to know when she will start devoloping onto a respondsibile and knowledgeable Teen. So let the information flow from caring parent to a more comfortable and self aware young lady. This way u know what she
knows about sex and you also can fill her in on changes that the boys will have too.
Just inform ur daughter about herself its. the best defence against having her experiment on her own and not getting the whole story about sex and how to protect herself from heartache, and know that the choices that she makes can and will effect her for the rest of her life. And that a baby can come later when she is ready to sacrifice the way parents do.
Good Luck & may patiences be with you.!!! :)