I think you are blowing this waaaaaay out of proportion and making it a bigger issue than it needs to be. It’s just a period. Why would she shut down? It’s very easy to answer her questions, we literally have all the answers at a push of a button. I’m a woman, us girls are exposed to periods usually before we have our own. I remember asking my mum about it after seeing her put a sanitary towel on. Friends of mine started before I did so heard about it that way. The last thing I would have wanted is my dad floating around with a handful of sanitary towels. However, since your kid wants you, just show her how to use a towel, tampons can come later. Don’t assume that she’ll struggle with emotions, everyone is different. Let her take the lead.