If you are not doing mitered borders, I would not sew the two fabrics together to add as a single border because straight cuts won't line up. If you want to do the easiest border, do a straight cut. As long as you measure across the center (or across 3 places and average) and use that measurement exactly along the edges, there should not be any problem. I think your friend was probably talking about wavy edges. She didn't mean to scare you.
As for the quilt itself and the level of perfection you talk about: Right now you are working a foot away from each little piece. You see every mismatch. Once the top is complete, sandwiched and quilted, the quilt will take on a whole new dimension. Odds are, what seems like a gaping error, won't even be noticeable. I have left some mismatched corners/points and when the quilt was done I couldn't even find them. Trust yourself. Besides, as a beginner you should be proud of every step you learn. Don't be so hard on yourself. You are taking the joy out of the process.
Last edited by MadQuilter; 02-11-2015 at 03:59 PM.