The Impostor Phenomenon (IP) and the Confidence Gap, which describe gendered differences in self-assessment and perceived ability, are psychological phenomena that can impact learning, retention, and performance. Our work focuses on the prevalence and interplay of IP and confidence among university students enrolled in web software development courses in Northern Europe. Using survey data with 392 valid responses that captured demographics, prior programming experience, IP scores, and self-reported confidence, we study (1) how IP scores are associated with gender, degree level, and prior programming experience; (2) how confidence is associated with these variables; and (3) to what extent IP and the confidence gap are associated with one other. Our results highlight that women report significantly higher IP scores and lower confidence than men, particularly at the MSc level. Programming experience was positively associated with confidence but not with IP, suggesting that IP is related more to identity than skill. Ordinal logistic regression and mediation analyses show that IP mediates (weakly) the relationship between gender and confidence, highlighting the need for interventions that focus on both skill development and psychological support.