Menarche is the first menstrual period. It marks a turning point in fertility, not an on-switch for readiness to have sex or to parent. Age varies widely. Cycles after the first bleed can be irregular for months or years.

People need pads or underwear they understand before the first stain shows up at school. They also need language that is not a threat and not a joke. Cramps, mood shifts, and the shock of blood are enough without extra shame.

Sexuality education that waits until after menarche leaves a gap. Fertility can exist before anyone feels like an adult. That fact is about biology and protection, not about rushing anyone into a role.

If periods are extremely heavy, extremely painful, or absent long after other puberty signs, a clinician should hear about it.