There is a difference in the two courses. The recommended course for Actuarial Science students is CSC1017 (Computer Engineering). The course you are currently registered for CSC1015 (Computer Science) is a more in depth course, though I'm not sure to what extent. This course is needed for those who intend to continue with Computer Science courses at a later stage.
I recommend you speak to a student advisor (the lecturers in the department). Their consultation times are on their doors, or you can email to schedule an appointment.
Be aware that the last day to add a first semester course is 15 February (tomorrow).