Rachel, I grew up having lots and lots of friends, always. I never had lonely times in my childhood or in my young adulthood. Now into my early 40s things are very different, and perhaps I have changed a bit, too.
I know exactly what you're talking about in your experience in church...and I have always made an effort to talk to people of any age, race, size, etc...I do that sometimes while standing in line at the grocery store. I don't look for people who look like me, or seem close to my age necessarily as I've always enjoyed conversing with all kinds of people. I do believe we all have something in common. I am introverted and sometimes shy, so I do need to sometimes make a concerted effort to talk with others, but I always feel good about it.