I say that you should leave it as is if the child is under 5. Over 5 then go ahead and make bigger. I make baby quilts 40x40 and that's good till they are about 4ish. Depending on how fast they grow. Then I make bigger about 50x50 for kids who are over 5. That is what I have done for my two kids and their friends. It gives me an excuse to make a new one for them as they grow and tastes change. If you want the quilt larger, I would do the black both front and back. It looks great.