A childhood belief about periods

I saw a commercial for tampons when I was little, and it was a mysterious thing to me. I asked my mother what all of it meant and she simply replied, "You'll find out when you're older, when you become a young woman." I remembered the package in the commercial and saw it in my mother's bedroom one day. I opened it and saw the wrapped up tampons. I was utterly mystified. My cousin was having her 14th birthday around that time and I overheard my mother saying, "Kelly is turning into a beautiful young woman" I decided to make her a card and thought the best thing to draw on the card were those little tampons I had seen. I drew them all over the card. When the birthday rolled around and she opened my card, she looked very confused. I had written "You're a woman now!" on the card, surrounded by flying tampons. It was a very very embarassing day and I didn't understand why everyone thought I was rude.