In the first episode of the Waltons it is 1933 and John-Boy is 16, so in 1963 which is 36 years later he should be 52 years old. Elizabeth was about 7, so she should be about 42 years old in 1963. In this Episode Olivia says that she's not worried about Jim-Bob and Elizabeth not being married yet because they are still young, but I don't call 42 years old as young.
John and Olivia celebrate their 25th anniversary in "The Anniversary," set in 1940, meaning 1969 should be their 54th anniversary, not their 40th.
Though the actual first landing on the moon took place in July of 1969, here it is depicted to take place near Easter of that year.
Opening Narration: The Moon walk was an epic moment in our history—a day that changed the world—and that same year my own world was about to change as well. What was waiting on Walton's Mountain wasn't quite a walk on the moon, but to me it was just as momentous.
Closing Narration: My mother had to wait just a little longer to finally see the ocean, and my children came into the world on the mountain where generations of Waltons had been born and raised before them. I learned that the love I received from my family as a boy on Walton's Mountain would serve me well in the years to come, no matter where I lived.