Agreed -- finish the quilt keeping all your seams consistent. When you get to the borders you can make them a bit wider to compensate for the smaller size if you need to.
Yes, Dottymo, I have a quilt that is living proof that you do not want to change machines when making a quilt. Even though I thought I had measured the heck out of the new machine I wound up with unmatching 1/4" and a real nightmare to assemble.