I have adjudicated Kiwanis, and I listen for musicality, style and interpretation above all. Be sure your harp is in tune, too! To prepare for an exam, use your metronome every day to make sure your tempi are at least close to the specified speed, and the technique should be up to the speed indicated in the syllabus. To overcome nerves, play through your entire program every day for at least two weeks before the exam, in front of your fake audience of teddy bears, dolls, lamps, etc. Record yourself if you have the equipment, and then listen to the recording and write down what you liked and did not like about your performance, then work on improving it. If you do this, you will have an accurate idea of how you are going to play at the exam, and it will reduce your fears immensely.
I have never seen “30s” as a speed; it must mean something else. How short are these pieces? Is it possible they are 30 seconds long? No tempo marking except “Gracefully”: the piece should not go so fast that it sounds frantic nor so slow that it resembles a dirge.