Virtual reality (VR) technology has become more common in engineering education. However, in most educational settings, there is still limited evidence regarding student acceptance of the technology and its educational advantages. This study examined how high-school students experienced their first VR lesson in environmental engineering, focused on ultraviolet (UV) water disinfection, during a university summer camp. A within-subjects pre-post design was used, involving 35 high-school students who completed questionnaires on expectations, learning confidence, motivation, and interest before the lesson. After the VR experience, participants evaluated the system's perceived usefulness and ease of use, perceived learning value, sense of presence, engagement, satisfaction, self-assessed comprehension, and overall enjoyment. Descriptive statistics and Cronbach's α were used to assess internal consistency, nonparametric tests were applied to compare pre- and post-session responses, and Spearman correlations were calculated to examine relationships between constructs and actual reported changes. Students rated the lesson highly for its usefulness, learning value, and ability to maintain attention. The evaluation of multiple constructs showed that participants rated them higher after the session than before it, while the gender-based subgroup analysis did not reveal statistically significant differences.