Just go for it, you will be glad you did. I have recently done four door quilts that are 40 x 80 pieced with the square in a square. I used a decorative stitch along the straight line and free motions meandering in the borders. That was the first time I had tried free motion. Since then I have quilted three quilts for kids and started on a twin size for my g-granddaughter.
My ggd's quilt is a log cabin and I did a no-no. I started on the outside of the quilt and worked in to the middle. I only had enough basting spay to basted the top to the batting, so had to pin to the backing. Once I started quilting I pined heavily on the block I was quilting on and when finished moved those pin to the next block. By starting on the outside once I got the borders done I trimmed off excess batting and backing and that reduced a lot of bulk that I would have to get in the throat of the machine.
I'm not recommending this process, but it worked for me and the quilt doesn't have any wrinkles on the back.