you need to be a rocket scientist, not customer service/safety
I disagree. For example, Jetstar ask you have at least a year 10 certificate. Not many rocket scientists I know have left school at year 10!
I will also say you guys seem great and well experienced. It is good to see people your age getting out there and trying. I have no doubt, somewhere in time, you will get there. FYI I started trying at 19, several interviews later I got in as cabin crew close to my 21st birthday!