Like kingofkabul, I'm also at the young end of the scale (based on the other candidates at the final stage at Cranebank). I'm 23 and was the second-youngest there - in stark contrast to the earlier selection where I was actually one of the oldest.
I graduated from university last year and have been working in finance/banking since that time. Apart from one gift 'experience' flight I've never been behind the controls of a plane. What really helped me in the interview was drawing on my extensive list of extra-curricular activities throughout school and university, as well as performance bonuses and appraisals I've had from work.