How come you only found out today? Your teacher should have known six weeks ago. You would have paid two months ago, too. Not a good idea to prepare last minute for an exam, but I wish you well with it.
If you still work on the Kabalevsky, work on short sections of a couple of bars and go over them ten or twenty times in a row. Start with a larger drop forward from the wrists and work towards a faster speed with small, quick wrist movements. Once you have direct accuracy, the speed should increase automatically. Focus on using the wrist and make sure you are not using the lower arm. Quickly get into the keys and out again. (A quick tap) Use your lower arm to move your fingers over the keys sideways instead of trying to move across the keys using your fingers. Make sure you lift well and don't get 'stuck' in the keys for a moment.
With the AMEB at grade 4, variety of programme is not an issue. Both Tanets and Melody are list A, so that should not be a reason for not playing it.
However, Melody is almost as fast as Tanets and is nearly all played with the left hand and requires maturity of expression. Musically, Tanets is a far easier piece.
About not panicking - proper preparation is really the best way. However, you have made a decision about how you have used your time - just work with full concentration as much as possible over the next few days. Give it everything you have got. An exam is not the end of the world - if you don't pass, you still can move forward in your grades and pieces. The reason for exams at your level is to learn how to manage the demands of structured practice / performance preparation and to receive a reward for your efforts.
Do remember that the exam really is of little consequence at this grade - although we teachers are loathe to promote such an idea (some students would never practice!) Do the best you can and treat it as a good opportunity to get feedback from someone other than your teacher - and hopefully you'll get a nice certificate.
Just got back from it, it went for ages. Pieces were good, I stuffed up a couple of times but kept playing, a couple of times I didn't depress the keys quite enough so they wouldn't play.Scales were good, majorly stuffed up the fingering for Bb minor, but it was either that or have the scale in a muddle, at least that way I kept playing.Sightreading was waaaaay too easy.Aural was better than I thought it would be. I didn't panic about remembering the rhythms, so I managed to remember them. Singing the higher and lower notes of a sequence was also not too hard. Middle notes of a tried I'm glad I practiced, but that went pretty well as well.I was shaking the whole way through though, whether from cold or nervousness or a combination...I don't know.
Topic: Exam! 