Well you don't HAVE to do 24 per year. 24 per year suggests you're doing 4 units per semester (each being 3 credit points). That's the norm for most full-time students, but if that's too much for you, just do 3. Doing just 3 units per semester still counts as going full-time.Do you know If you have to do 24 credit points a year? How many did you do?
I usually do 24 credit points (8 units) per year, but I deferred the first semester of last year, and only did 2 units in the second.