Easy DIY flannel swaddle blanket

I had bought some snuggle flannel material at JoAnn's for my burp cloths and thought it would be fun to make a matching swaddle blanket.  This was a super easy project for any novice sewer.  Here are some pictures of the end result. 

The blanket ended up being about 36"x36" in size.  One side is the polka dot pattern and the other is a solid pink.  Overall, I think this turned out pretty good.  I was trying to make a square shape, as some other mom blogs have recommended square swaddling blankets rather than rectangle.  I noticed my edges aren't perfect and my square is a bit questionable, but live and learn, right?! 

Another thing I'm not quite sure on with this blanket is whether the blanket will stay formed once it's washed, or if I should be adding some stitches in the middle or something.  Anyone else out there have experience with that?  I'm only hoping to get better in this endeavor to make baby gifts, so wish me luck on the next one:)