Dear Sisters everywhere
Shaming girls and women about their periods is a thing invented by patriarchs and is not natural. Your periods are totally natural. Learn to say "this is Mother Nature! don't defy her!" if you can.
Now something every girl and woman needs to know.
the story of menstruation
During our first 200, 000 years we were matrifocal societies. Women were honored and respected because they had the sacred gift of bringing forth new life. In addition to this they were primary breadwinners. Every day they could go out and gather fruit, vegetables, roots and tubers, nuts- a great variety of foods. So they always provided something to eat every day. The men went hunting, but hunting requires luck, and if they were unlucky on any given day, they might return empty handed. Also, in addition to food gathering, women were expert botanists, and over time acquired a great understanding of medicinal plants. So they gave us babies, food, and medical care. those are plenty of reasons to get the respect they always had. But there was something else. Men had a mystical notion about menstruation. They called it "the wound that heals itself". It was also known as "the wise wound" .This mystery was represented by a stylized vulva, a symbol that appears everywhere in ancient caves and rocks. Male shamans knew they would not be respected if they did not posses something feminine, and they adopted this vulva symbol to give themselves credibility.
When patriarchy finally arrived to dominate societies, they went to great lengths to subdue and suppress woman power. So it was that the new god managed to get a man to "give birth" as Eve was born, so to speak, from Adam. This reversal of a millions years old tradition (and of Mother Nature!) was necessary to stake out the men's claim to dominance. In the Patriarch's Playbook, women are portrayed as allied with the devil, not to be trusted, and "cursed" to bleed every month, among other sufferings. What a long way we had come from the days of the wise wound, and shamans need for feminine credibility!
One final thought: Women have always been strong, and you still are. The ferocity with which patriarchs have have tried to maintain their "dominance" is one way to measure how powerful women really are!