['I need to past a test next week but since I am well prepared I believe I will have no trouble doing it.', 'Are you nervous? Or do you have amazing confidence in your ability?', 'I am feeling pretty good about it since I think I am very well prepared.']
Do make sure to get a good nights sleep before hand. That is just as important.
I need to past a test next week.  I am well prepared, so I believe I won't have trouble passing it.