Perfection is highly overrated IMHO. Maybe this is not the right pattern for you. I have had fabric that I could not cut until I found "the perfect pattern" - then I had no trouble cutting into it.
If you are truly just worried about making a mistake, I'd suggest you write out the steps and follow them with extra care. If you don't know the pattern, do a test block with different fabric.
I think you'll do just fine and your quilt will be beautiful.