On Friday, I went to the University of Chicago Class of 1983 dinner hosted by the university’s president, Robert Zimmer, and his wife. I don’t know what possessed me to sign up for it, which I did before I knew that any of my friends would be there. Aware that I would know at least two people, I managed not to back out.

First, there was the question of dress. My wardrobe, suitable for a reclusive life, lacks style and variation. I had a vague idea that this might be a dress occasion, but wasn’t sure. One of my friends called to ask, “What are you wearing? I heard that people get dressed up, but I also heard some wear jeans.” By then I’d already decided on slacks and my dragonfly blouse — dress casual, more or less. I figured that if I were the most underdressed person there, those who remembered me would not have expected anything else.

I didn’t expect to recall anyone outside my immediate circle, which was very tiny, and perhaps a few people from the dorm. As I peered at name tags during the reception, I was surprised by how many of those names, if not faces, jogged my memory — possibly more names than I remember from high school. I also ran into the man I’d sat next to at graduation. I mentioned that we’d laughed together at President Hanna Holborn Gray’s ponderous delivery of her speech. Then she seemed ancient; in reality, she was only 53 — six years older than we are now. How time changes your perspective.

When I’d gone to my 10- and 20-year high school reunions, I’d been fascinated by how much people had aged even in 10 years, how many men had lost most of their hair, and how many people had added padding. The combination of sedentary occupations, relative affluence, packaged and prepared food, and complacency seem to age the body in that way, turning even lean teenagers into rounded adults. I observed this on Friday, but I was also struck by how few were significantly gray — L’Oréal for women, Grecian Formula for men? — and by how few of the men were bald.

At these reunions, I’ve also seen wide variety in the rate at which people age. A few people at my 20th high school reunion looked 10 years older than everyone else. I don’t mean aging caused by exposure to the elements, like lines, leathery skin, and powdery look that come from being in the sun. Some facial structures simply seem to succumb more rapidly to gravity.

I noticed this, too, at the reception. Between mature stoutness and aging of the face, some looked very mature. On the other hand, I recognized a woman at my table instantly — not someone I had known personally, but someone who had lived in the upper house — simply because she had changed so little. At least in the light of the tent, her fair complexion was unlined and firm, and she had avoided putting on that bit of padding that can make one look uncomfortable in one’s own skin.

At 10th reunions, people seem to fear comparison — that they will feel ashamed of their lack of accomplishments,t that their career or title is not lofty enough, or that they won’t measure up in some way, especially to people perceived as popular overachievers, who in turn may feel that they haven’t lived up to their promise or expectations.

After 25 years (and probably much sooner), people have accepted who they are and what they have done; status matters less. A few classmates provided biographies listing impressive careers or academic or social recognition, but the talk at my table was mostly about shared memories — late-night runs to Harold’s Chicken, relationships, apartment living after the dorm, and restaurants and bars.

I remembered one man across from me, too far away to talk to, as well liked, although I didn’t know him. Afterward, he came around to say he was sorry that we didn’t get to talk during dinner. When I said I recalled him although I was sure he must not know me, he said that of course he did. I was skeptical, but he seemed so sincere that I understand why he is liked.

I don’t have a lot of memories in common with anyone. I didn’t go out much or explore the neighborhood, I didn’t have many friends, and I didn’t participate in much of the social or academic life. Years later I finally understood what life there could have been for me and how I could have grown had I been more sophisticated and outgoing, and less overwhelmed and depressed.

As we were waiting for our ride, I mentioned that, during my first year, I had attended a sherry hour with Eudora Welty as the guest of honor. Perhaps sensing my discomfort, she took a shine to me and spent a significant amount of time talking to me. That conversation should be engraved on my brain and heart, but it isn’t; at the time I didn’t know who she was. As odd as that sounds, it’s true. I knew that she was a writer, but that’s all. Later I understood that I had received once-in-a-lifetime encouragement in literature from an American writer whose stature might equal that of, say, a Brontë or even Austen, and I hadn’t been able to appreciate it.

That anecdote sums up my college experience. I had countless opportunities to hear from world-renowned intellectuals and influencers, and I frittered them away out of ignorance.

The day after I asked one of my friends if she noticed how things that had seemed so important then had proven to be insignificant and how the angst over them now seems almost silly. Her response didn’t answer my question, but it echoed a page in the memory book. She said she had come here as one of the top students in her school only to find herself one among many and that she kept challenging herself. I didn’t really quite follow the rest, but I felt a similar sense of opportunities not understood or not taken.

Will I go again in five years? I am more likely to, if I can. I don’t want to keep making the same mistakes.