congrats. if you are going to find out boy or girl before the birth, you might want to wait and do something that will go with the nursery decor and sex of the baby.
for my oldest grandson i took all the squares i cut out of the corners when making his crib sheets and did a simple patchwork. however, gave it a solid backing and handquilted waves, puffy fish, little slender schools of fish, sea turtles, sea grasses, air bubbles. he is 3 and wants it with him anytime he is going to sleep.
for his baby brother i did large squares with appliqued sail boats, then hand quilted waves.
just let your inspiration hit you, you've got time to enjoy thinking up what you want to do while you are waiting for the little one.