Assalamualaikum wrahmatullah wbarakatuhu When does fasting becomes obligatory on women ? If before menses then what signs of puberty is considered for it ?

Fasting becomes obligatory once she reaches puberty, which happens with whichever of four signs comes first: menstruation, coarse hair growing around the private parts, discharge of maniy with desire whether awake or asleep, or completing fifteen years, as the scholars have stated.