When I was a child, I use to never understand why no one wanted to be friends with me. More than likely this was one of the reasons, because I did not understand that not everyone found those interests to be as interesting as me. As I got older, I stopped caring what anyone thought. I would study and research whatever caught my fancy and mostly would often talk outloud to myself about it.
Eventually there would be others that would either gravitate towards me and engage in conversation about the interest, or would go away. More often than not, those interests would help me find the type of friends I was interested in having. Now that being said, I did have to learn moderation. Just because someone is interested in the Roman Empire does not mean they want to hear about it for the next 10 hours!! Lol. So with those friends I would bring up things going on around town, like any haunted houses in the area that we could go to. Making another interest become something social.
Its about taking an interest, expanding upon it, and learning more about those around you. You learn more as you get older I have found if you just push yourself a little.