I would suggest giving her the information from a trusted source, so that she does not have to get it off the streets (so to speak). There are books written for girls of her age that answer a lot of questions. The link below is for one that is highly recommended. And several more are given on the same page. I hope this will help.
She is going to keep getting information. Is there a reason why you don't want her to get information from her? I would say keep open dialogue between your daughter and you. Ask her what her friends shared with her every day. Then if you are fine with what she learned, cool. If not, gently correct it. As long as she knows that you know better, she will listen to you, ultimately.