Hi cliff, im more then half your age and im still new to this industry aswell but from what i've read on here i will try to help a bit!
From what i can gather, doing a modular course for your fATPL is alot cheaper then an intergrated course. Modular is 40k and intergrated is around 70/80k
Then you need to do a type rating which is like another 20k. Im really going on what i've read on these forums so it might not be 100% accurate but people like fly_antonov, redsnail and WWW have a much better idea.
I dont think 40 is too old, infact i think some airliners prefer to recruit older more mature pilots. But be realistic, now is a very bad time to start training (unless it picks up after your training). Pilots with alot more experience and experience on type are being laid off and cant find jobs. Theres a huge back log of low houred pilots looking for work.
My advice would be, if you can afford all the training without going into debt then go for it. However i wouldnt go into debt with the current situation of the industry because you will be very lucky to get a flying job.
This is very brief and reflects my knowledge of the industry but i thought i'd give it a shot! As mentioned before wait for the more experienced people to post before making any choices.