This paper examines how post-secondary education (PSE) enrollment among adults aged 25-45 responds to local economic conditions in the United States. Using nationally-representative data spanning 1979-2024, we show that PSE enrollment is countercyclical among mature students during time windows spanning the mid-1990s to the mid-2000s. Mature students account for nearly half of the economy-wide countercyclical enrollment pattern among men, and for the entirety of the economy-wide countercyclical enrollment pattern among women during those years. In earlier and later periods, enrollment among mature students is largely acyclical. The countercyclical enrollment patterns among mature students are primarily observed at 2-year colleges, and are largely driven by individuals with partially-completed degrees remaining in school. However, we also find that downturns increase the likelihood of beginning a new degree among several demographic groups, namely Hispanic men, White women, and Black women. At the graduate school level, we observe increased enrollment among White women and decreased enrollment among Hispanic men when economic conditions deteriorate.