Hi Shelta,
Congrats on getting into Jetstar! Let me reassure you about the training, in the 4-5 groud schools this year Ive only heard of one person failing and apparently they werent actually putting in any effort and decided that she would leave on her own accord after failing a number of exams. You get multiple attempts on your exams, the pass rate is 80% for everything except drills and equipment location and operator which is 100%. The trainers are really friendly, they want you to pass and will help you if you are having any problems. As long as you take it seriously you will do fine.