Financial decision-making is a common part of everyday life, involving investment and risk choices that adults frequently navigate. Nevertheless, most research on the emergence of financial literacy has focused on formal education and the comprehension of basic economic concepts. This has resulted in a gap in our understanding of how children develop sophisticated financial decision-making skills, the cognitive and behavioral capacities associated with youth financial decision-making, and whether real-world market experience can produce measurable decision-making advantages in youth. Research on adult financial decision-making has revealed mathematical ability to have a strong and robust association with higher quality financial decision-making. A greater ability to delay gratification and higher risk tolerance have also been associated with better financial choices, with greater working memory capacity measures showing some, but not consistent, association. However, expertise theory and experiential learning frameworks suggest that lasting skill development emerges from sustained, meaningful engagement with consequential decisions. This raises the possibility that real-world contexts of voluntary and sustained financial engagement may also be associated with higher quality financial decision-making. One environment in which youth naturally gain advanced financial experiences is the card-collecting hobby, making card-collecting youth an ideal population to study. The present study examined financial decision-making experience and cognitive and behavioral factors to understand which factors have the strongest association with higher financial decision-making quality in youth. Youth between the ages of 9 and 17 completed assessments of financial decision-making quality, delay discounting, risk tolerance, working memory capacity, and mathematical ability. Across both financial decision-making measures, mathematical ability was the most robust contributor, replicating the adult financial literacy findings in a developmental sample. Collecting experience (as measured by length of time collecting and engagement intensity) also contributed independently of mathematical ability on one measure of financial decision-making quality, with two collecting profiles demonstrating more optimal performance than Non-Collectors. Overall, the results of this study indicate that financial decision-making competence in youth reflects both cognitive resources and sustained, consequential real-world experience, providing implications for the design of educational interventions that leverage structurally similar contexts to support financial development.