I joined Google’s software engineering team in 2001 when I was 55 years old. That’s right, I said fifty-five, as in five five. I was the oldest employee at Google for the entire four years I was there.

What did I do? I was not an executive… and I was not a manager… I was simply a software engineer working alongside all my dear colleagues whose median age was probably 25 years younger than I was. My age never seemed to be an issue with anyone. I felt like I was just another member of the team and I felt I was accepted that same way.

There is no such thing as being “over the hill.” There is only becoming irrelevant. To keep from becoming irrelevant, I never stopped learning. When I started my career back in 1975, we still used punch cards and mainframes, programming in Fortran and PL/1. In the 1980s, the promising new technology was applied artificial intelligence. I was fortunate enough to have a great teacher who recognized my abilities in a Lisp class and got me a job with his AI research team, where I not only learned more about software concepts, but also learned the importance of staying on top of cutting edge technologies as they appeared. I devoted myself to a life of constant learning.

In the mid-1980s I became intrigued with this new thing called object-oriented programming. I learned everything I could about it and wrote my master’s paper on “A Design Methodology for Use with Object-Oriented Programming,” which is probably now buried somewhere in the stacks at Boston University, if universities even still have stacks.

So after ten years of programming in Lisp, in 1990 I moved on to the new object-oriented language at the time, C++. Then a few years after that, the web burst on the scene and I moved into web development, using more new technologies like HTML and JavaScript. Learning, constantly learning, was the key to all these transitions in my career.

I watched as others my age either moved into management and starting climbing the corporate ladder and others simply became irrelevant and became unemployed or switched to whole new careers. At almost all of my early jobs, my managers would notice that I was a gifted software developer and somehow concluded that I should become a manager. Not knowing any better, I would accept the promotion but then time and again I learned that I hated being a manager. I loved developing software and that’s what I wanted to do. It all became crystal clear one day when my manager walked in my office and saw me working on a program and said, “What are you doing working on software? You’re a manager now!”

I had found what I loved doing, and I was very good at it. So why would I ever want to stop doing that and do something entirely different by becoming a manager? I was advised on many occasions that if I didn’t move up the ranks of the corporation, I would never be able to retire. But every time I tried moving in that direction, I hated it. It caused me a huge amount of stress and, besides that, I felt I was terrible at it. I occasionally tried taking courses to make me a better manager, but they bored me silly. I just wanted to go back to my computer and solve some problems by myself. Finally, I declared one day in 1996 that I would never manage anyone again. I didn’t care if it meant that I could never retire. I thought I’d just figure it out later.

In 2000, I migrated from Boston to Silicon Valley with my newly acquired PHP skills for the dot-com boom that promptly turned into the dot-com bust right after I arrived. By then I was very used to working alongside people who were half my age. In fact, I loved it. I kept fully employed for ten more months, but then suddenly one day I got laid off.

A friend of mine sent my resume along with his recommendation to this little company of about 200 employees that seemed to be one of the few companies left that had any promise of success. When Marissa Mayer called me to do my phone interview, I was very clear right up front that in spite of my age, I was not interested in being a manager. She assured me that they would not expect me to move into management. In fact, she said they had just decided that they wanted to hire some people with decades of experience but who did not want to be managers.

I got the opportunity of a lifetime precisely because I did not want to be a manager. It confirmed my lifelong belief that if you find what you love to do, then devote yourself to doing it the best that you can, then you will find a way to make that work.

Four years later, I retired with a wonderful life. I made many close friends along the way and still feel very close to my colleagues at Google as well as other places I’ve worked. I married the man of my dreams in 2008, before Prop 8 took away that right. We have traveled together, and I took up art, and, yes, I’m still learning new technologies simply because I enjoy it. In the past month, I’ve tackled Ruby and now I’m working on Ruby on Rails, picking up along all the other technologies every good Rubyist ought to know, like git, gems, and bundle. And just in case you haven’t done the math, I am now 69 years old.

My advice is to keep doing what you love, never allow yourself to be diverted from it. Always be willing to help others along the way with kindness and generosity of spirit. And you do not ever have to fear becoming irrelevant.