I'm sure I've told this story before, but finding a club to support is all about gateways.
In 1998, I was in Munich as part of a short-term exchange program and saw a Munich match -- an 1860 Munich match, which would be City to Bayern's United if anyone gave a shit about the club, which now languishes in the 2. Bundesliga, forever doomed to play in a 69,000 seat stadium with no prospects of ever filling it.
As 1860 collapsed into obscurity, I saw Thierry Henry for the first time and followed Arsenal fairly loosely because of him. Then, a few months after the fact, I saw a clip of Steven Gerrard fire a shot through the heart of Olympiakos, then he followed up 17 months later with a similar strike against West Ham in the 2006 FA Cup Final. Because of Gerrard's ability to strike from just about anywhere, I got into Liverpool just as Robbie Fowler came back for a second, and final, stint at Anfield. Then I started to learn about the history of the club. Now, after surviving the fossilization of Fernando Torres, Hicks/Gillett, Woy, and Andy Carroll, I follow Liverpool as intensely as any American club. In fact, I was listening to the Chelsea match driving across Nova Scotia, and as the second goal was being scored, all I could do was turn down the radio, embrace the silence, and try to find some positive to salvage the day, which Crystal Palace pissed away within minutes of starting their match against City.
All I can say is, if something pulls you to a club, go with it and see where it leads. Maybe you pull for a big club because of the atmosphere at a stadium, or maybe it's a small club because you saw them pull off the most unlikely of Cupsets. The only person you'll have to answer to on any of this is yourself, so make it a fun trip.