nanabd

Hi! I have a couple of questions I'm hoping someone can me with. I'm making a quilt for my grandson out of flannel. I'm doing the Double Slice pattern from Missouri Star Quilt. What I've done so far is cut the 10" squares and then cut that into the 3-1/2" and 6-1/2" pieces. I didn't realize until that point that I probably should have washed the flannel first because of shrinkage. Here's my question. Should I stop at this point and wash the cut pieces or continue on sewing them unwashed? I haven't done a flannel quilt before so I don't know what would be the best way to proceed. I'd appreciate any help and advice you could give me. Thank you!!