Why do most women get their first period around age 12 when their bodies are usually not well developed enough to safely carry a baby to term?

Question

Why do most women get their first period around age 12 when their bodies are usually not well developed enough to safely carry a baby to term?

In: 12558

Answer 1

Didn’t know that was the average. I was 15, my sister 13. I am the older sister, developed much later and am often mistaken for the younger sister even with my grey hair(I’m almost white at 36 which is common in our family). I was very very premature at birth so that may play a role in it.