This study explored the interaction between baseline cortisol (BC) levels and spatial elements—specifically classroom size and window view—within a virtual reality (VR) early childhood classroom setting, to assess their impact on the cognitive functions of young adults (aged 19-28 years). The research involved 160 university students (80 male, 80 female) in South Korea. Participants' BC levels were determined through saliva assays, while additional data on demographics, fatigue, and sleep quality were gathered via questionnaires. They undertook computerized tests assessing memory, attention, and cognitive flexibility both before and after exposure to one of four VR scenarios, which differed in classroom size (large vs. small) and window view (natural vs. built). Regression analysis, adjusted for initial test scores, showed no main effects of VR conditions on cognitive outcomes. However, a significant moderating effect of BC was observed: participants with higher BC levels performed better on the card sorting task in large classroom settings compared to those with average or lower BC levels. No differences were noted in the small classroom condition. These findings highlight the potential interplay between the physical aspects of preschool environments and the differential susceptibility of adults, suggesting implications for optimizing educational practices through enhancing cognitive flexibility.