My mom could always leap into the coldest water. Every summer when we visited my grandma in upstate New York, my mom dove straight into the freezing lake, even when the temperature outdoors hit the 50s. The dogs, who usually trailed her everywhere, would whine in protest before paddling after her, and the iciness left her breathless when she surfaced. “Just jump, Lil,” she’d yell to me, laughing, before swimming off to vanish into the distance. But I never could. I didn’t think much about that difference between us, until I flew north to be with her on the day she’d chosen to die. When my mom found out in May last year that she had pancreatic cancer, the surgeon and the oncologist explained to our family that cutting out her tumor might extend her prognosis by about a year; chemotherapy could tack on another six months. A few days later, my mom asked if we could spend time together in Seattle over the summer, if we could get lemonade at the coffee shop while …