Ann, don't stress out over it. You mite try cutting your pcs just a bit bigger, then trimming if necessary. Try cutting ALL 2 1/8" pcs at 2 1/2" then trim down after you've sewn them together. I'm sure (hope) you'll see this will help. Practice makes perfect (sometimes, lololo)... I've just found when they call for a such a small pc to work with, I up the size a bit then trim down.. Be sure you do a scant 1/4" seam too. Hope this helps. 
J
Last edited by Oksewnsew; 02-22-2017 at 06:52 AM.
Reason: change wording