T.F.
You daughter is in 2nd grade.
Around here, communication started WAY earlier than that about our bodies, periods, etc.
If you want you daughter to know the truth you need to be communicating with her.... no topic off limits. If you can't or don't feel comfortable doing it, then get in a car and drive or go for a walk so you don't have to look eye to eye. Get some quality books for girls, read them and then share them with her. She needs to know she gets her facts from mom because if she doesn't, she will find "facts" from peers which are not always "facts".
I teach school and yes I hear children talking in 1st grade. I was teaching 3rd grade yesterday and during indoor recess I had a group of girls at the art table giggling and all they were talking about were the boys and who they wanted as boyfriends and to kiss. Believe me, your daughter knows more than you think she does. She is probably confused and needs you to confirm facts.
My advice is to be honest... answer her questions in an age appropriate manner and maintain open communication so she knows she can always ask you and get the truth. Yes, it happens frequently and in most schools including private, public and Catholic!