I'm going to guess that they will have some leniency for the first test at least, for you to get used to their system... and even if you did get below the required mark, they will also take into account your motivation ... your anxiety about this shows that you want to do well ... I doubt they would kick you out when you've tried hard. Besides, you haven't even started yet, you might do really well in it And if you do find it harder than expected, you could always discuss it with a tutor there or somebody ...