Answering S1tPilot - and my opinion...
xxx
At 42, I would say GO for it... and hurry...
The ICAO and now the US/FAA have approved pilots to fly to age 65.
That would give you a career of 20+ years.
After some 10 years, you could upgrade to be captain...
xxx
The age limit extension to 65 gives you an extra 5 years. In the days of the 60 age limit, I would not have really recommended you to consider to start an airline career past age 40. Nowadays, I would say the limit might be 45...
xxx
In 1991, when I lost my job with PanAm, just had passed my 48th birthday, and went to cry on the desk of "human resources idiots" who had no idea of what is aviation and what is a pilot candidate should be, and this with the airlines that had carved their expansion from my airline. They openly told me that yes, I could be then hired as a 727 F/E and could be hoping an upgrade as 737 F/O a couple of years later, strictly based on seniority. The 737 was nicknamed the "light twin" with PanAmigos... Under NO circumstances would I ever be captain again (I dont care really, but the salary is quite different). My years as captain and worldwide experience would be of no help in a career raising the gear between ORD and DTW, and pushing the IDENT button if given that privilege. And... forget ALPA.
xxx
Thank you "friendly skies" or "the professionals" (you know these nicknames in the USA airline industry). So I went overseas, and got a job as direct entry captain on 747s... And now fly until I will hit 65...
xxx
I often am in the selection board for new hires, and here pilots do get hired by pilots, not "human remains" department (did I spell right?) and I always support mature individuals around age 35-40, now even 45. Dont worry if you need a couple of extra simulator sessions and start wearing glasses.
xxx
All the best to you...
Happy contrails