My mother is 56, and is a professor of Chemistry.
I tried teaching a little bit of computer programming the last time I visited her, she initially found it rather hard to pick up, but mainly because of the way I taught it to her. I mean, why the hell would I talk to her about conditionals and for-loop? I switched my methodology and taught it like how I would teach it to someone who doesn't know what for-loops are.
She did find it very interesting to develop static HTML websites, all within five hours. So, nope. It's never too old to learn anything (let alone programming).
With computers however, you need to know the basics of math (and/or science and logic, in general). I found it extremely hard teaching it to my ex-girlfriend who has degree in English Literature, but doesn't really have a strong foundation in mathematics. When I said computers could think only in binary, she was all like what's binary. Fair question, but for me to cover the basics, it's gonna take a while, so I decided to temporarily abandon my efforts to get her into programming.