First year students at the University of the Witwatersrand in Johannesburg, South Africa, were surveyed about their perceptions of Computer Science before and towards the end of their first year courses. The aim of this research was to investigate how the students' attitudes changed during these courses and to assess the impact of the innovative breadth-first curriculum that has been developed in the School of Computer Science which emphasises the fundamentals of the discipline and the mathematical nature of Computer Science. The results show that most perceptions did not change much or that there were changes in both directions. More students, and particularly female students, were positive about their own understanding of the nature of Computer Science after the course than before. However, when asking specifically about jobs and course content, there was not a substantially deeper understanding at the end of the course of what content they would expect to encounter in a Computer Science course or working as a Computer Scientist. Fewer students, particularly male students, thought that Computer Science and mathematics were closely related after the course than before and this was an unexpected result, which may be the result of discrete mathematics topics being taught in courses separate from those in which continuous mathematics topics are taught. Students became less positive about working with computers after the course, a result which supports prior research, but is an issue for concern as computers will play some role in their future careers. The students found the courses challenging and different from their expectations with few students finding the courses unenjoyable.