Have I messed up?
 

I bought a kit from Keepsake Quilting for the Labyrinth quilt. This is the first big quilt that I've made in years, and I wanted the colors to be good together, so I chose a kit. Since some of the colors are dark, I prewashed all of them before I started cutting it out. Well, here's my problem that I woke up to at 4:30 this morning... I DIDN'T wash my muslin backing. I bought the good quality muslin, but in my effort to hurry up and get started, I completely didn't think about washing it. Will the back shrink now when I wash it? I hand quilt and have completely gotten the big medallion/star done and am moving right along... now I wonder what I should do. Any help would be appreciated.

Muslin does usually shrink. What I would do in your case is to complete quilting the top more densely than you might have. It may crinkle more than usual, but think positively - the crinkling may be wonderful!

Totally go with it, as ArtsyOne says.

Most shrinkage is actually due to batting so you should be fine

Thank you all for your replies... I woke up worrying about this and just couldn't get it off my mind. It's for my son and future daughter-in-law and I wanted it to be special.

Ditto what ArtsyOne says. And think positive!

I've never spent this much on one quilt at one time before.... Scared I'd cut it wrong, was so thankful I thought about prewashing since it has dark colors and light, and then finally, TOO LATE, thought about the backing. Feel better about it now though. Thanks for y'alls encouragement!

It will be special and the kids will love it.

I think it should be just fine.

Muslin does shrink... sometimes a lot. Maybe you could wash a bit of it after measuring and see if it shrinks more than you can accept. Better to undo the quilting and start over than to not be happy with the finished quilt.