This article explores the complex relationship between gender, mathematical self-concept, and choosing to pursue a STEM degree program in Austria. Additionally, it evaluates the accuracy of mathematical self-perception relative to performance across genders. Employing quantitative methodologies including linear mixed-effects models, matching algorithms, t-tests, and chi-squared tests, the study analyses samples comprising 260 to 302 individuals. The findings indicate that female STEM students exhibit significantly higher initial mathematical self-concepts than males and demonstrate a propensity for optimistic self-concepts. In conclusion, choosing an academic STEM career path necessitates an above-average mathematical self-concept for women.