You should be worried, they will want you to show them a job you have done, that includes the certificates, and if you have not certified a job, you will fail.....
Ignore the bit about failing, the have had your money you are in!!
Get an afternoon appointment,if they come in the morning hungry,they will eat you for breakfast
The questions they ask are mind boggling,it's a wonder anyone gets through it without a nervous breakdown
Sorry,I'm only joking.its really much worse than that