My lack of Native American ancestry

I know this is a long shot, but I wanted to check genealogy websites to see if there were any Native Americans with the last name Blair. I thought this would be really cool to find out if i had any ancestors that were Native American. It took me awhile to locate a free website but it's possible, so I typed in Blair and recieved six different results. Unfortunately, I have never heard either one of my parents or grandparents ever hint at there being a Native American ancestry. So, I tried my mother's maiden name next. That was not even an option, absolutely zero results. i don't know what my paternal grandparents maiden name was but i had my maternal grandmother's name, which was Johnson. I knot it's a common name but I got tons of results, so much in fact, that I didn't even have a chance to look through them all because it was so lengthy. It would be really cool to find out if I had Native American ancestry, although I know the bloodline by now would be way into the 20's or 30's at least. And maybe I'm just going about this the wrong way, but finding out my ancestry in general would be very fascinating.