Using a rich data set of all SAT test takers from the 2004 through 2008 high school graduation cohorts, we investigate the impact of state-specific school age-of-entry laws on students' pathways into and through college. We document that these laws do not impact the probability that a student takes the SAT; however, we find strong evidence that students who are expected to be the oldest in their school cohorts based on their state residency and birthdays have a greater probability of taking an Advanced Placement (AP) exam and tend to take more AP exams. We also find that relatively younger students are more likely to attend two-year colleges before attending four-year colleges and are less likely to have earned bachelor's degrees four years beyond high school graduation, but eventually catch up to their older peers six years beyond high school graduation.