Why is this woman smiling? She’s about to take the Certified Cheese Professional exam, concluding eight months of intensive study. At 65 (believe it or not), Erin Selby is not a typical CCP candidate, and her motivation isn’t typical either. Most people want the credential for career advancement. For Selby, passing the exam would cap a cheese journey that began more than four decades ago, with a college year in Switzerland. But her determination to master the subject really kicked into gear after an intimidating encounter with a cheese clerk.