Don't worry about the test. Comparing it to driving, as a lot do, isn't really fair. Look at this way. Worse thing in a plane is you stall. So you practice that and the recovery. Worse thing in a car is you plough into a brick wall at 50mph. Not many driving schools actually have you do that, instead you stand on the brakes at the appointed time.
And so we could go on. If you break downthe training, you could teach someone to fly a plane BASICALLY in about 10 to 15 hours. The rest comes in nav training and emergency drills. In addition, millions of people take a driving test every year, not as mant take a skills test so to uise that staistic will only affect your confidence. Also bear in mind that the CAA don't peer over the examiners shoulder all the time. The DSA do peer at driving examiners. There is no pass and fail rate for each examiner contrary to popular belief, but there is an average figure, a national average of a pass rate. And the examiner (driving here remember) needs to be around that figure or else his boss wants to know why. So in effect there is a pass fail rate that the examiners need to stick to. All test centres have at least one route guarenteed to fail a pupil.
In the air it is different. You have had all the training, there are no surprises really, what the examiner is looking for is your ability to be safe and make safe decisions. When I did mine I started dropping like a stone in the steep turn. Part way round I levelled off and told him that I wasn't happy and was losing control and so returned to level flight, did it again and all was well. It is all about being safe and making safe decisions based on the information you have available.
More than anything else, enjoy it, yes enjoy it. It is 2 hours plus of flying with everything thrown in. One thing to bear in mind, if you lash something up, TELL THE EXAMINER that you know it has been lashed up. He might let you do it again, and he then knows that you know it wasn't good. Don't for one minute think "he didn't notice that, I'll keep quiet about it" for hr WILL have noticed it, very much so. Driving examiners are the same in that respect. I clipped a kerb on my HGV test and let out a stream of obscenities about it. The examiner then replied, I take it you know you shouldn't have done that? I told him yes and the reason it happened (too fast on approach to the turn) and I passed. Clipping a kerb is an instant fail but he knew that I knew it was wrong and why it happened so he was happy.
That's my advice anyway
Good Luck