For admission to the B.Sc. Economics course at St. Xavier's College, having Mathematics in Class 12 is typically a key eligibility requirement, as the course includes quantitative and analytical subjects that build on math skills. If you studied Commerce with Computer Science instead of Mathematics, it might impact your eligibility. However, it's best to check the latest guidelines on St. Xavier’s official website or contact their admissions office, as requirements can sometimes vary by year and specific program.