I'm considering a career move...
What age do airlines look at a candidate and consider them "too" old?
There are a few threads on this subject knocking around. Probably more limiting than age is you life situation. The main questions to ask are:
Can you afford the training?
Do you have any of the responsibilities, likely to come later in life, that might prevent you taking a huge pay cut to instruct, and do you have commitments that will prevent you moving abroad to find work as a bush pilot/instructor, whatever?
Where do you want to end up? Flying a jet for an airline, or at a turboprop/GA operation?
If you've spent any time on this forum you'll know you're unlikely to walk into an airline job straight out of training, so you need to consider what you will do to get there, and how you will fund it.
I'm going through training myself so hardly a voice of experience, but the above is all food for thought. Make sure you do your research and have a plan in place before investing in training.