Am I racist? or just stereotyping?

I'm not black, nor white. I live in the US. But I have this thing when I see certain white people, I immediately get "nervous" and look for hints of racism. I guess it's stereotyping? It happens to me mostly when I see white people that have a country accent, specially women, and bleach blonde hair, middle aged. I don't get this feeling with white people that don't have the accent, and I don't get this feeling with young people. I get it mostly from middle aged ladies with the country accent, but not all of them. There is also something that I can't explain about how nice or mean they look. Am I racist, or just stereotyping and is this good or bad, or is it a survival tool from our brains? Like there is this lady like this that just got hired where I work, that has all these characteristics, and I just try to avoid her as most as possible. Maybe it's just a past experience thing where the brain takes a shortcut? because most situations I have encountered of hate or racism in the past have been with people that look and sound like that?