Is this unusual?

Everyone has a certain "look" that they prefer, and that their brain and body are automatically more responsive to.  Call it a matter of "taste".  This can easily cross the lines that people call "race".  It's not terribly unusual...perhaps about as common as 20-somethings who adore 40-somethings.  You needn't feel odd, or worried by this.

I can't tell you WHY anyone develops their particular "look" in the way that they do, but I can tell you that the mechanics of whatever's happening inside you are exactly the same as those that cause some boys to be fascinated with brunettes while finding blondes disturbingly unattractive.  Everybody does this, in one way or another.  It's just human.

A couple of things to be careful about, though:

1. Don't dismiss out of hand the potential of people around you who don't satisfy your taste in all respects.  The love of your life might be beside you, in a European or African or Native American guise.

2. Don't objectify Asian men because of the effect their appearance has on you.  They aren't talismans to collect, or squeeze the juice out of & discard.  They're men just like you, with lives and concerns just like yours. If you find yourself befriending a guy who you wouldn't, if he looked European/African/American, then you're astray - demeaning both him and yourself.

Don't worry.  There's nothing wrong with having a particular "taste" when dating.  Everybody does.  Enjoy!

We all have our preferences. 

Definitely not unusual. Plenty of people have their “type”.  Whether it’s into Asian men or Latino or short, tall, hairy, hairless, old, young.. we all like what we like and sometimes for reasons we don’t even know or realize. I guess the trick is to not let that be the only thing, because that’s no way to vet who is worth spending time with and who you should bother getting into a relationship with. 

I have no idea how common that specific attraction is, but there's certainly nothing wrong with it.  If you're attracted to Asian guys then pursue one who you like for a boyfriend.  Everyone has their own preferences and attractions regarding potential mates.

You have to know what you like. The term for what you prefer is “rice queen”.