My impression from my experience is that the 'right' age bracket to be coming out with your fozen ATPL is between 21 and 25 and that the further you are from that the more you will struggle to find someone willing to offer you a first position on a jet, if thats what you're after. If you can imagine a bell curve chopped off at 21 on the lower end and tailing off to retirement age with a strong peak at 23 you might get an idea of your chances due to age. Its not impossible that you will get your first job at 50, and somebody probably will, just a lot less likely. Starting at 30 you will already find some doors closed to you but it is by no means impossible. I would not recommend getting into the career if you do not want to struggle and you want to have an easy life over the next few years. If you don't mind a few setbacks and can't imagine doing anything else then go for it and don't look back!