WHEN TO BEGIN PURDAH
A girl should begin observing purdah for strangers even before she reaches seven years, and for relatives from the age of seven. I believe that as long as a girl has not adopted purdah, she should not be allowed to wear even a bangle. Her clothes too should be very simple and inexpensive. In this there are worldly as well as Deeni benefits.
[Hakeemul Ummat Moulana Ashraf Ali Thanwi – Rahimahullah]