The use of artificial intelligence technologies in education has huge potential to improve teaching and learning by providing personalised learning experiences, on-demand academic support, and automated feedback. The emergence of generative artificial intelligence has introduced a new category of educational technology that is changing how students search for information, solve problems, and engage with course materials. This transformation is especially relevant for computer science students, who can benefit from using AI tools not only for learning but also for programming. The purpose of this research was to investigate the main drivers influencing the adoption of the ChatGPT tool among Romanian students enrolled in a computer science educational program. An extended technology acceptance model (TAM) that includes output quality and perceived impact as external variables has been specified and tested with a sample of 165 university students. The results show that perceived enjoyment and perceived usefulness have the strongest direct influence on the behavioural intention to use ChatGPT. The influence of perceived ease of use on perceived usefulness and behavioural intention was not significant, suggesting that it is not a relevant variable for computer science students. Another finding is that taking into consideration indirect effects, perceived impact of AI tools on education and future professions, and perceived enjoyment emerge as equally important for the adoption of ChatGPT.