People can change and grow at any age. The key is inner motivation.

It's not age as much as mindset

It's never too late to wise up. Life would be better if it happens early, but even a centenarian can benefit from learning the truth and freeing himself from religious scams.

I was in my late 20's when I awoke to the truth. I wish it had happened earlier, because my wife refused to look at the evidence, and when I left our religion, she took the two children (toddlers at the time) and disappeared. Losing my family was a horrible experience. I recall holding a knife to my chest, trying to gather the courage to plunge it into my heart. Happily, I backed out of that plan, and I have found a happier life than I had ever had as a religious person. Life is much better without being a victim of religious myths.

It has to come from them, like it probably was for you, I doubt you changed your mind because someone, especially younger, came to you with arguments that convinced you. Has to be self realization through believing the overwhelming evidence or lack thereof.

I never really gave it much thought until college. Then we studied a little bit about Religion. That's when I noticed that they were all remarkable similar. That's when the lightning went on for me: they're all made up stories passed around

It is true that age hardens beliefs and habits and it is also true that some people's hardened habits and beliefs will go to the grave with them. This includes people still wanting to deposit a check physically in a bank, going to withdraw cash from a teller instead of an ATM, refusing to pay any bills, taxes, fees, licenses online. These people will have to die out for new things to take hold. The adaptive nature is cultivated against natural instincts wanting to resist the change.

I grew up not especially religious, default Xian because we weren't Jewish or Catholic. As an Army wife the chapel community offered lots of support and other young moms for friendship and companionship. I bought in for a while. I always had that WTF moment, but I needed support, especially far from home with small children. It was also keeping my marriage together. When I knew positively that the marriage was dying I also took a hard look at the Xian concepts, and realized that was a whole bunch of what was wrong. My ex is still sucked into that especially conservative xian crap. I tried to maintain the church connection as a single mature female, but most churches are not welcoming of single mature female adults. That was awakening. The movie ZeitGeist and a few other helpful sites, and I hung out my atheist flag. My adult kids said "about damn time."
As for your folks, old habits are really hard to break, and they likely find comfort in their beliefs. Also check what reinforcement they're getting. Faux News is especially toxic.

I'm not sure which question the poll is for...
How old is too old to change one's mind or how old I was when I saw through the smoke and mirrors?

Lenin had the same idea. Once all the old women had died then religion would die with them. The trouble was that new old women came along to replace them.

I came to the realization when I was 5 when my dad failed to explain why Santa Claus is not real but the idea of God himself is real which led to a huge argument.
Which is stupid because Santa Claus has a better chance of being real than God; a fat man entering your house in the middle of the night without your knowledge we call that a burglar probably even a stalker or ax-murderer... then we have God; a pissed being who demands worshiping and loyalty without question but you can't see, hear, or feel him and your reward is eternal paradise when you die... possibly because the chances of you getting the reward is at minimum of 10% if not lower... A paradise that you can't feel or care about because your dead...
I dunno, but it could also be that Ive been accused of being a smart-ass when I was a kid and I don't think much as changed

The older I got, the more I saw through all the b/s. My sister is different. The older she gets, the more she believes.

There is no set age on changing one's mind. It all depends of the person, the subject matter, and how well the alternate view is presented.

I attended a baptist parochial school until I was ten. It was shortly after I left that school that I knew the story was a con. It does seem those who are ambivalent or noncommital often turn to religion as they get closer to the grim reaper. Won't happen to me though. I'm already old and neither ambivalent nor noncommital.

Forcing religious indoctrination upon children should be considered child abuse, because, well, it is. Thankfully my parents in the 50s South agreed to let us figure it out on our own. My sister is devoutly Christian, and I am anti-religion. My interest and study of astronomy really cemented my atheist views.

We're not dogs; we can choose to educate ourselves our entire life.

One is never too old to change one's mind about anything but there are many reasons why people don't. We all learn things in different ways, some need proof, some need to see it with their own eyes, etc, etc, we all have different experiences in life in what has worked for us or not. There are so many variables.

I'm glad to see that at least some people can come around in their later years. It may be rare, but that makes it more beautiful!

I thought about trying to break my parents faith, but their entire life was centered around ther rreligious beliefs. In the end I decided the effort would only drive us further apart, and if I succeeded they woudl be miserable about how much of their lives were wasted. I just could not see any possible positive outcome to such efforts.

At 11 I figured it out. I was helped along by my crazy mother, who unwittingly exposed me to the ridiculousness of religion by being wildly indecisive about it.

I attended a Catholic high school. In my senior year I was given a term paper to write for my physics class - any science subject was okay. Because my older brother had a few books of evolution, I chose that subject for my topic. As I read "The Naked Ape" and other books I began to see the sense in science and the nonsense in religion. So, in an odd twist of fate, my parents sent to Catholic schools for religious instruction, but it turned out to send me away from religion.

Wisdom doesn't come with age. One either has a capacity for it or not.

As a child and teenager I was never taught any real form of religious beliefs even though I was baptized at birth as. Protestant!!!

What finally changed my mind was the SE Asian Circus of the sixties and seventies, it was reinforced by the Latin American conflicts of the seventies and eighties.

If there is a god(s) he/she sure does not give a shit who is killed, murder, or maimed in his/her name!!!

Old is 10 yrs older than I am.

I changed my mind at 46. I guess you can teach an old dog new tricks

In the Beginning you're

Not old enough to know better

Then You're
Old enough to know better
BUT
Not old enough to know

Then You're
Old enough to Know

BUT not old enough

Then You're
Old Enough
BUT not old

Then You're old
and then you're not

No such age, it is indoctrination on one hand, habit and tradition on the other

Some folks feel ungrounded without those
Some folks feel a sense of freedom

Depends on who it is, age is not so much a factor as life experience and critical thinking skills

Too old for what? If you mean when did I become agnostic it was when I was a mature adult 65 or so.