Being 40+ is not a disadvantage, infact it may well be an advantage!
In the age of SSTR, pay for Line Training etc, you are just as welcome in the 'airline' market as anyone else. More so.
Outside of the airlines there are a great many flying positions that would value your age and experience. My Biz Jet owner actually prefers guy's with your profile. We don't pay for our type ratings!!!!!
Follow your dreams - if you want it, go and get it!