Cassie McIntyre pushed her grocery cart through the fluorescent-lit aisles of the local supermarket, her two toddlers strapped into the front seat, their tiny hands clutching at boxes of cereal. It had been a long day, a blur of diaper changes, tantrums, and endless rounds of "Paw Patrol." The weight of single motherhood pressed on her shoulders, a constant ache she'd grown accustomed to. At twenty-four, she felt both old...