Being the only kid in town who’s into astronomy or poetry is lonely. It’s also proof you picked it yourself.

An interest nobody around you shares could not have been handed to you by a group. There was no crowd to join and no credit to collect, so whatever brought you to it came from inside. That does not make the evenings less quiet.

Since the people exist and are simply not nearby, go and find them. A forum, a club two towns over, a library section, one teacher who knows the subject. Keep doing the thing in the meantime, because the loneliness tends to be temporary while the interest usually is not.