We study an accelerated three-year middle school math curriculum in a large urban district that lets students complete Algebra I and Geometry before high school. Admission is based on 5th-grade math scores, with a cutoff near the 80th percentile. Continued eligibility requires at least a B grade in the previous year; program completion is highly correlated with an index of non-cognitive skills. Following students for six years after high school, we find treatment effects that vary widely by non-cognitive skill and gender. Marginally eligible boys with high non-cognitive skills are 33 percentage points (ppt.) more likely to complete calculus by 11th grade and 12 ppt. more likely to complete a STEM or business major within six years. Boys with lower non-cognitive skills take more advanced high school math but show no significant college effects. Like their male peers, girls with high non-cognitive skills are more likely to complete calculus by 11th grade (+17 ppt.). Their rate of STEM/business majoring is unaffected, but they shift from social sciences to core STEM fields. Girls in the lower non-cognitive terciles are also strongly affected, with more advanced high school math, higher entry to selective four-year colleges, and more STEM/business degrees (+12 ppt.).