The Remarkable Retirement of Edna Fisher - E. M. Anderson - Bog

You're never too old for adventure.
When you're a geriatric armed with nothing but gumption and knitting needles, stopping a sorcerer from wiping out an entire dragon-fighting organization is a tall order. No one understands why 83-year-old Edna Fisher is the Chosen One, destined to save the Knights from a dragon-riding sorcerer bent on their destruction. After all, Edna has never handled a magical weapon, faced down a dragon, or cast a spell. And everyone knows the Council of Wizards always chooses a teenager-like the vengeful girl ready to snatch Edna's destiny from under her nose.
Still, Edna leaps at the chance to leave the nursing home. With her son long dead in the Knights' service, she's determined to save dragon-fighters like him and to ensure other mothers don't suffer the same loss she did. But as Edna learns about the abuse in the ranks and the sorcerer's history as a Knight, she questions if it's really the sorcerer that needs stopping-or the Knights she's trying to save.