The short answer is no, you are not too old. I was a little older than you when I did it a few years back. Heck, my airline (regional) recently hired someone at 62, which while not common is not rare either in this industry. People decide to become doctors and go to medical school at your age. It can be done.

The bigger question is- can you do it? Don't underestimate the significant amount of time, money and mental effort involved. How would you feel about going back to get a college degree (or a masters/ PhD) at your age? The amount of effort is similar if not even greater. By 50 most of us are decades removed from any sort of formal leaning process, and the brain just doesn't absorb things like it did in your 20s. On the other hand, you have a life time of life experience, wisdom and maturity (hopefully) that your younger colleagues lack. This can be an asset, and airlines recognize this. I've leaned into my grey hair during airline interviews, like anything it's about how you spin it.