Do you think that its weird/inappropriate that I am completely open and honest with my 4 year old daughter when it comes to my period?

I'm someone who is never embarrassed to speak with other women about physically personal things. Periods are certainly not a taboo topic to me. When it comes to my daughter, I know someday she will have a period of her own and I feel it's a totally normal thing and shouldn't be some shameful secret. I want her to have an understanding of it way before it actually happens so that it's not some big scary event the day it does finally arrive for her.

I'm a stay at home mom so I spend all of my day alone with her (and my new baby) and I commonly pee with the bathroom door open. More than once she has walked by and seen my bloody pad and asked why/what's happening/ if I'm okay. I simply explained to her that when girls grow up they bleed from their privates sometimes, that it's normal, and that I'm not hurt and I'm going to be okay. I also explained that this is a private thing that she can ask me anything about but at the same time shouldn't be talked about with her friends or at school because it's up those those girls mommies to talk to them like I talked to her.

I told my friend about this, and she seemed shocked. She said it was inappropriate due to her age, but I feel it was a normal healthy conversation?

What's your opinion on this?