'Phot' this is indeed the 'age old' (pun not intended) question as once upon a time if you didn't start at 16 with a 'learners permit' you where behind the 8 ball from day one with those that did so. Now however if cashed up & determination is high a commercial job at 40 or so is doable but with obvious limitations. The diff paths that you could take after completing a basic CPl vary a lot. Am sure many here will be more o fay with it all than I am but for the RFDS & perhaps Corporate it would indeed be a slim chance starting out so late but obviously nothing is pretty much not impossible. I'm not saying you won't make it but you don't need sunshine blown up yr ass either in this game
The main thing that I found as I struggled up the at times rickety ladder of flying ( as I was considered too old once) was that age versus hrs/experience is something that you might find bites you in da bum a fair bit. At 40 yrs it's kind of expected that you would have many 1000's of hrs in a variety of general charter Ops etc & turbine experience chucked in there too to be employed by the RFDS for instance.
But there would be a job for sure out there for you given the right attitude just don't plan it all or put all yr eggs in one basket for a Corporate/RFDS job at the end of yr training as expectations/assumptions are the mother of all F... ups especially in aviation:-)
Good luck with it all just food for thought here buddy, yr a long time dead, well so they say:-)
cheers
Wmk2:-)