This paper examines how the timing of college field specialization affects students’ educational and labor market outcomes. To study this question, I exploit a 2011 policy change at a Midwestern flagship university that incentivized only engineering students to declare a major earlier. I develop a conceptual framework in which students learn about their match quality across majors through course grades while accumulating credits toward graduation. Earlier major declaration increases exposure to major-specific high-level coursework, but also reduces flexibility to exit the initial field as a result of increased specialization, creating a trade-off. The framework generates predictions that I test empirically using a difference-in-differences design. I find that the policy increased within-engineering switching by 75%, reduced exits from engineering by 80%, and improved academic outcomes, as reflected in higher GPAs and a 14% increase in honors graduation rates. LinkedIn-based career data further indicate enhanced early career outcomes in engineering: greater persistence in engineering positions, longer initial job tenure, and a greater likelihood of attaining managerial roles. These results suggest that, in settings where students retain flexibility in major selection, incentivizing early major declaration can improve student-major match quality.