Mate, Ive just taken mine....
Aslong as you pay attention and listen to what the instructors tell you, you will be fine..
If you are with other people that are re-newing there CBT, DONT try and keep up with them as they may have been riding for a few years. Tell the instructors that you need some 1 on 1 help if you dont feel confident as the last thing you want to do is muck it up when your out on the road..
Hope this helps,
Best of Luck,
Charlie