I don't think age is the issue in IT so much as the generalization that more experienced individuals tend to be more set in their ways. I don't like generalizations, but I think they are appropriate when it comes to this topic. I'm right around the same age and I have been quite successful in IT. If I consider what separates me from some other "older" engineers, it is that I never stop learning. Some of my peers seem to live in the past and as we all know, the IT field moves quickly. Things that were bleeding edge 5-8 years ago are old hat today.
Since the beginning of my career the field has moved from physical to virtual to cloud, which really is just someone else's datacenter with an API on it. The only constant in the field is change. It is relentless and if you do not ride the wave you will end up irrelevant. Today the field is rapidly diverging into what other, more elegant, thinkers have aptly termed "white collar" vs "blue collar" IT. There is a great talk given by Jeffrey Snover of Powershell fame where he describes the difference between the two: https://blogs.technet.microsoft.com/ser ... collar-it/
The fact is that us older systems people are being given a choice: we can adapt and overcome or we can be left behind. The days of rack and stack hardware in the datacenter are behind us. Today's infrastructure is defined in code, fronted by REST APIs and accessed via Python, Powershell, Go, etc. The systems field is rapidly transitioning into development instead. Instead of procuring and installing servers and storage, we're creating automation frameworks and developing unit testing and continuous integration. Well, that is what I'm doing anyway. And I've had no problem finding work. My most recent foray into a job search yielded multiple competing offers in the same week. And I do not live in a major east/west coast metropolitan area (although I do hail originally from one).
If you have legacy systems knowledge and can learn how to program in an object-oriented language you will have companies fighting to hire you. Today's developers are being tasked with yesterday's systems knowledge, and you are uniquely positioned to bridge that gap. If you have more specific questions you are free to PM me. I am always happy to help another systems person out.