I'm really open with DD, as a single mum she sometimes has had to be my tampon fairy and bring them to the loo since being little. She knows I 'have blood' as she calls it and about periods in general.
I switched to a mooncup a while ago but DD has never encountered it. She came in when I was in the bath, saw it on the side and asked what it was. I said it was instead of a tampon/pad to catch my blood when I'm on my period.
She then asked if I held it under me when I wee'd to catch it. I automatically replied, no, it goes inside me in my vagina and stays there to catch it. She said 'ewwww' and left it there.
Bit worried I explained too far with the inside me part.
I've had to start explaining to 6yo dd about sanitary towels as she asked me loudly in a public loo why I had poo in my knickers .
Completely depends on your dc btw. My dm got me the body book when I was around 8 and I found it helped me understand. Two years later my sister thought my mum had given her pure filth and refused to read it all.
My DC are 2 and 3 years old, it is rare that I get an unaccompanied loo trip when they are awake and so they have seen me open various sanpro products and asked questions about them. I try not to be too graphic but I don't tell lies, I try and say general things but answer questions accurately. I don't think your description/explanation was over the top or unreasonable, the more you normalise periods etc the less frightening she will find it when it is her turn.
OF COURSE it's fine. The more you talk to her about her body the better. You should continue to add to these talks, discussing how she and she alone has control of her body, and if she has any questions, about anything, she should always come to you. You are laying a wonderful groundwork. Excellent job!
@WorraLiberty sorry-she obviously isn't aware yet of the changing size/shape of a vagina. The size of the mooncup made her eyes widen when I said where it went-I could see the cogs turning even though she didn't verbalise it.