We are our harshest judge. I'm sure that what you see as errors or imperfection would not even be noticed by another viewer. And as a previous poster said, perhaps your vision exceeds your current skill level. And that's okay, because as you work on this project your skill level will develop with each block.
My first quilt was 4" squares with a ruffle. I had no clue - nothing lined up. I wanted something that looked like the perfect quilts I had seen in magazines and at quilt shows and frustrated myself because what I saw in my head wasn't what I was producing. Fast forward a few years and I like what I'm making, but I'll never produce what some of the ladies on this board can do, and that gives me something to which I can aspire. You will too, and have fun learning at the same time.