I have heard of a lot of pilots that realised when they were in their mid 30's that it's what they wanted to do and so they took the money out of their mortgage. I mean, how many pilots fresh out of education fund their own commercial training and how do they do it?
For that reason, I imagine for the operators willing to take on ATPL(F) F/Os the majority of the available pool will be 30+ as presumably the twentysomethings will be in the respective hold pools or in line-training for their sponsor organisations (barring exceptions).