amongthestars,
If you really want to fly, you will get there. Persistence is 9/10 the effort you require to sometimes get into this job - strange but true.
I know of people who, like many, took HEAPS of interviews to get into flying. Some of them fly with me. And they are the best crew in the sky. Some get in first go, others not so easy. Just the way life goes sometimes.
Jetstar are constantly on the lookout for crew. Unless your email/letter saying 'thanks but not yet' stated a time limit, I'd say that you should give it another go. Don't let this, or anything else, step in your way to achieving what you really want.
Take care. Safe flying!
MS2