B.B.
Well, I got my first training bra at 8, body odor at nearly 9 (I remember because my sis put deo on me during summer vacation that year lol) and I started my period at 10yrs old. ( the year before they showed "the movie" lol) but I had 3 older sisters so I already knew about it. My mom had to explain it to me at 5 yrs old when my oldest sister leaked because I wouldn't quit asking what happened. Not much detail of course. I don't think your daughter is too young to know about it. I know that Tampax use to send out a "starter kit" and stuff on how to talk to your daughter about it several years ago. You may want to google it and see if they still do.
Hope this helps.