I know this is an old thread but past experience has nothing to do with it, you can either do it or you can't. I took my FATs yesterday and 2/6 of us (including me) passed.
I am 18 and just finished A levels in Economics & Business, Enronmental Studues and Geography (not the sort of qualifications you would relate to pilot training). A couple of the other guys had degrees in engineering and failed.
It's really just about innate ability, and if you are going to do your FATs, don't stress while you're down there because you can either do it or you can't. It's probably the most mentally challenging thing I've ever done though.