Thanks, ladies, for all of your kind thoughts. I am back on the right track now. My problem was twofold. One, I just plain read my ruler wrong when I out out one fabric, and, two, I was expecting all of my points to line up exactly.
Now I double check my ruler, and my points are almost all lined up, but the one or two that aren't....well, they are not noticeable by anyone but me. I seem to have this belief that if I pin two seams exactly, that is how it should end up when I have sewn them. Unfortunately, sometimes they just don't.
I use a foot that guides my 1/4 seams, so that was not my problem. I have used only one ruler, so that wasn't my problem. The problem in both cases was me.
BUT, I have learned a lot. I didn't know how to make quarter square triangles until I tried this Ohio Star pattern...and I didn't know how to...and this may be something that works just for me....start sewing about one inch down if I am connecting a corner that has seams there already....then I turn the square over and sew that last inch from the other direction. It just works for me. I also learned that I have a 4 1/2 inch square ruler that works wonderfully for these quarter square triangles. I always wondered what that ruler was for!! I think it must have been a gift, as I don't normally buy a ruler that I don't need.
I now have ten squares done, and they are beautiful. I will easily finish way before Christmas, and I am no longer frustrated...for now. :)
Thanks again.