Using data from the National Longitudinal Study of Adolescent Health, this study examines the impact of high school cohort composition on the educational and labor market outcomes of individuals during their early 20s and again during their late 20s and early 30s. We find that the positive effects of having more high school classmates with a college educated mother on college attendance in the years immediately following high school decline as students reach their later 20s and early 30s, and are not followed by comparable effects on college completion and labor market outcomes. The results suggest that factors that increase college attendance are not always sufficient to improve college graduation rates and longer term outcomes.