Definitely piece it.

Piece it.. don't worry.. I've made lots of mistakes either in cutting or in figuring how much I'd need and ended up short.. It's fine to piece, in the end you'll have to look carefully to find where it is. I've even seen quilts in magazines with a piece part. No worry, just piece it and go on.

I would piece it.Have done it many times.It's called Patchwork.
Good luck.

Yeah! You go, girl!

Personally, I would piece it, who is going to know it isn't supposed to be that way?

I would piece it and press it and then decide. If the fabric is dark, you may not be able to find the seam at all.
sometimes mistakes lead to great discoveries!

Piecing has my vote

I agree that piecing it would work well since it is a Turning Twenty quilt - esp. if it will be machine quilted.

Can you cut them even shorter and repeat the mistake, so it looks like part of the pattern?