1,431. The Lower Sign of Maturity

Hilchos Ishus 2:2

Growing two pubic hairs after reaching the age of 12 is called the lower sign of maturity. Once a girl exhibits this sign, she is considered a naarah (“maiden”) for six months. From the last day of these six months on, she is called a bogeres (mature). The period from becoming a naarah to maturity is just these six months.

Hilchos Ishus 2:3

Once a girl has reached the age of 12 years and one day, until she reaches the age of 20, if she does not grow two pubic hairs, she is still considered a minor even if she exhibits the signs of infertility. If she grows two pubic hairs in this time, even at the age of 20, she is considered a naarah for six months and only after that a grown woman.