The 87-year-old wore a silk dress she had sewn herself. The bright blue fabric featuring yellow, turquoise and lavender flowers pulled at the eyes, and against it, the pale pink stones of her necklace seemed a conservative choice. But that’s not why she wore it.

With a smile, she explained that she had picked the beads less for the statement they made than for the promise they held.

“They’re supposed to help you get a boyfriend,” she said, laughing.

When the woman tells people she is not far from 90, they show genuine surprise. She has…