I don't think you're a racist. In fact, your desire to not offend someone of a different ethnic background is a true sign of wisdom and maturity. You and I both know that God loves all people equally. We are all his children, and Christ died for people of every skin color and ethnic background. I love what Paul wrote to the church in Galatia, "There is neither Jew nor Greek, slave nor free, male nor female, for you are all one in Christ Jesus" (Galatians 3:28). The way I figure it, if God doesn't look down on any certain ethnic group, then neither should we. But noticing that people are different isn't the same thing as looking down on them.
Not too long ago, I was in another city on a subway very late at night. I looked up and realized that I was the only white person on this train. I'll be honest--I was very aware of my difference in color. The next morning, I had breakfast with an African American friend. I told him about my experience. He said, "Jim, I feel that way every day." His comments reminded me that, while racism remains a very real problem, it's not racist to be aware of the distinctions between people.
When you lived in a multicultural area in Arizona, it probably didn't take much effort to get to know people of different races. Most likely, you didn't even think about developing an ethnically diverse group of friends--it just happened. But when you moved to a different part of the country, it might have made it more difficult to meet friends from a variety of ethnic backgrounds.
I encourage you to go out of your way to meet people who look and even think differently than you. I'm often most blessed and challenged when I get out of my comfort zone and relate to people who have a different perspective.
It's unfortunate that we live in a society where there is prejudice. Unlike some of your acquaintances, you can be a part of the solution rather than the problem. This might sound harsh, but prejudiced people are ignorant people. They just can't see beyond a person's skin color. But God sees what's inside, and that should be our goal as well.
Find out what religious leaders are saying and doing about racism.