There's no hard and fast rule, Harris. It really has to be about your comfort level, your audience at the moment, your environment and how it will react to your assertion of your atheism. I make no bones about my atheism, but then I'm here in Cleveland, Ohio, where the religiosity is nowhere near so thick as it might be elsewhere.
As for being invited to church, I wouldn't go, myself, and I don't miss it. Last time I attended church regularly was probably 40 years ago, plus, so it's nothing even remotely like a regular part of my life. I'll gladly walk my daughter down the aisle when the time comes, if it comes in a church, but at this point in my arc, I won't compromise myself to suit someone else's delusion.
Welcome to A/N, Harris,
Loren's right, there is no "hard and fast rule". But, there's a point where you should probably ask yourself, "What kind of a world do you want for your descendants?"
I would suggest you read this book, just in case you think there isn't anything you can do to help shape the future your grandkids will have to be a part of.
I'm glad you at least found Atheist Nexus Harris! Welcome and you are not alone! Maybe you could sort-of hint around with your son and maybe he will confirm he is an Atheist and then the two of you will have each other to talk to?~ Melinda
Harris welcome to the site. I was also brought up Southern Baptist and went to private school. I went through many religions before I finally made it to Atheism not too long ago. I guess only you can tell when the time is appropriate to bring up your Atheism. I am the only Atheist in my family and only one other knows at this time.
My goodness man you're 60! You've raised a successful family and led a fulfilling life to date. If you were in danger of losing your livelihood or life itself, I would tell you to tread lightly. It seems to me that you should feel confident in coming out or not coming out as you see fit. You have already demonstrated that atheists are the type of people one would want to be like. There are of course things in your life that cannot be gained from your short post, but based on what you've said, I would ask, "Why should you keeping living a lie?" Who and how does anyone benefit from that? You suggest that your son might be an atheist, do you think he has the same reservations that you do? How do you think it would affect him if you came out first?
Like I said, from your post I can't garner enough specifics to give you definitive advice. But, ask yourself, what's important to you; weigh the consequences, and realize the evidence you have given points to the fact that you deserve to be taken seriously, whatever your final decision is.