I was 10, so 9.5 doesn't seem like a big stretch to me. I can see it sneaking up on you at that early age, though. First of all - did she know what it was? My mom was 10, too, and her mother had never told her a thing about menstruation and she thought she was dying when she woke up in a puddle of blood

. And her mom still didn't really explain much about it. Anyhow, the first thing I'd do is make sure she knows it's totally normal. If you haven't had any sort of puberty discussions yet, now would be the time - and I think a good, frank book is a good way to go - you can talk it over with her and show her whatever pictures they have to explain about the ovaries releasing eggs, etc. Another important thing to tell her is about how long it will last and that because she's young, it might be sporadic and be several months before it happens again or that it might come back every month.
And I'd do something a little special for her. Like a mom/daughter day out doing something a little "grown up" - like a pedicure or manicure, or a fancyish meal somewhere (even if you just go to a not fancy restaurant but fancy yourselves up

)
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