I agree that you have to be completely prepared for the fitness test. If anything, you should make sure that you’re able to do more than they’re going to ask you, because you might find that your nerves stop you from performing as well as you would have liked to – so if you’re over-prepared you should find that you can still get through it regardless. You should of course be able to tell them all about why you want to join the army, and your experience up to this point, as they’re going to be interested to hear about all of that.