One of the major differences between homeschooling and conventional schooling is the fact that typically, life and learning experiences (the two are inextricably linked) do not occur with a large group of people the same age. Theater, sports, music, zoo class, and assorted field trips tend to be a family affair. You become accustomed to hanging out with people of all ages, rather than your friend automatically being the person closest to your own age, and their family members regulated to "annoying siblings" or "the mom." For me, this was often even more the case: because my family started homeschooling when the movement was novel and strange and because my mother spoke on the topic, adults wanted to talk to me as "exhibit A," while their children met me as their introduction to homeschooling.
I'm not sure whether homeschooling, happenstance or inborn preference played the greater part, but this trend only continued as I grew older. For several years, one of my closest friends was my neighbor's younger daughter. I worked at the Cincinnati Museum Center during school hours, so made friends with the adult volunteers. I was always very comfortable and at ease with them.
Then I entered the world of the traditional lever harp. Most harpers start either very young - they take lessons as children - or later in life, often towards retirement. I was sixteen and right in the middle, and in general, I've stayed there. I do meet some harpers close to my age, but most are on one side or the other.
My final encounter with the age gap came in culinary school. Once again, I was surrounded by people who were just out of highschool - given or take a few years - or people a decade or two older starting a new career. I tended to feel more kinship with the older students than with the "kids," but I've had good luck getting along with both.
Does it really matter? In the end, common interests and dedication trump age every time. If there has been any difficulty, it comes from the generation gap in terms of pop culture and common views - quite simply, we don't always get each other's jokes. For instance, in the kitchen one day, I made a "crunchy frog" joke to absolute silence. I've been the only person to laugh when my teachers made a reference. I was completely boggled to find out that many of my younger classmates never check their email. And who can live without their own printer? (All right, that may be a writer thing.)
Speaking of writers, that's another area that spans the gamut of ages, but I don't tend to notice it as often. A big part of it, I'm sure, is because there are almost no physical reminders. Another component is that if a joke does fall flat, it doesn't land in an obvious abyss of blank stares. But then, there's the fact that we writers tend to collect information and trivia, and we're more likely to get jokes that don't fit our generation, background, or chosen (non-writing) career.
... a bit like homeschoolers, really.