Is menstruation considered a sign of puberty in women?

Answer

In the name of Allah, the divine duties, including prayer, are obligatory if the signs of the obligation are met. For males, the sign is either the completion of fifteen lunar years, the appearance of coarse hair, not the fine hair, on the pubic area or the occurrence of a wet dream, i.e. emission of semen while dreaming. Any one of these signs is sufficient for puberty. For females, the sign is either the completion of nine lunar years, the appearance of coarse hair on the pubic area, the occurrence of a wet dream, or the start of the menstruation. If any of these signs are found in males or females, it is said to have reached to puberty i.e. the person became mature enough to do the religious obligations. Allah knows best.