I dated a guy who was 40, when I was 51. His parents were in their late 60s. We often went to his parents' home for dinner, to whom he wasn't out, and I also went with them to other local social functions, even church services.
Very decent & nice farming people, his mother likely knew her son was gay, and that I was his lover. But my BF told me his father was totally clueless. He said he couldn't bring himself to discuss the matter with his mother, much less his father, but he was certain she understood.
My BF loved to have me join him for dinner at his parents' farmhouse, because I got along great with them. Yeah, I had to be a little careful about what I said or discussed, but it was no hardship, and I always enjoyed their warm hospitality (and not bad farm cooking). And my BF thanked me for getting his parents to talk around the table, since he claimed when it was just the 3 of them there, nobody spoke a word during the whole meal, making it an ordeal for him.
One Christmas Eve I was invited to the parents' farmhouse, where 2 of their daughters and their own families had also driven from out of state. Their custom was to open presents before midnight, and I was astonished to find there were gifts for me, too, especially since my BF told me no "stranger" had ever been invited to this family tradition before. It was clear to everyone there, except perhaps my BF's father, that he & I were more than ordinary friends.
To answer your question, it wasn't a big deal to me that my BF wasn't out to his parents. I'm a "go with the flow" kinda guy in most social situations, and unless I run into outright hostility, I'm relaxed & friendly with everyone. I also have no shame about who & what I am, and have total self-confidence. If they don't like or accept me for being gay, that's their problem, not mine; I won't lose any sleep over it.