I don't think girls should learn about periods from a book, their Mom should be capable of explaining it. I've always resented my Mom for just handing us a book to explain it.
I much preferred a book! Maybe it was the way my mum explained it but I had a million questions i didn’t feel i could ask, and she made me feel like it was some hush hush whispered conversation. My mother’s biology skills are pretty crap too and much of what she said didn’t even make sense to me. I remember “when you’re a lady, once a month blood comes from your bottom”
A book i could go back and re read, or find another book if one didn’t explain it. I found going into proper detail helpful.
In the end it used to really piss me off when my mother would constantly put everything down to “it might be you starting” when i knew, biologically, i was around two years away from my first period.
I offered my dd’s the choice. I said i could sit down with them and explain it all, or they could have a book and then come to me if they needed to. They both chose a book.
Some of the girls at dd’s school have misunderstood explanations- at least one thinks you pee blood. Diagrams are invaluable for learning the structure of the reproductive system. The difference between the urethra, vagina and anus is pretty important!