Just a personal experience for you guys: I started my flying training when I was in my early thirties. I had a good previous employment record which probably helped. I was able, in the middle of the recession, to get a job with a LCC and am now at a major international airline. Everything worked out exactly as I wanted and I am very happy in my job and career.
However - I have been VERY lucky in this regard. I know people of similar ages who for no good reason, have not been able to find employment in the industry. Despite the law in the UK, which outlaws ageism in employment, most airlines get around this very easily. Nobody has ever sued them (to my knowledge) so there is no case law.
It is only now that I realise just what a massive gamble I was taking with my career. It paid off in my case, but if I was to have my time again, I wouldn't take such a risk.