I just looked at that list again
http://www.mathkangaroo.org/mk/centers.html

It looks like they only have centers in 32 states so far, even though there were competitors in 37 states last time.
http://www.mathkangaroo.org/mk/state_directors.html

This makes me think more centers will open up (but I could be wrong).

You have brought up the dilemma that while you wait for new centers to open up, other centers could fill up. I'm going to wait a while.

You could see if someone near you (a school?) would be willing to host a center.
http://www.mathkangaroo.org/mk/start_new_center.html