Why is it important to know Miriam's birthdate in chapter one?

I think it really is to tell us how much she has been through at such a young age. Her identity is recognized as an illegitimate child of Nana and Jalil. Her mother referrers to her as a harami or "bastard half child" (loosely translated). This sets the stage for the heartbreaking portrait of her and other women’s' struggles in this story.