I'm a hairstylist, and I think that the longer thick hair is the better sometimes, because the length weighs it down. Since your hair is short, I'm sure it has a tendency to become "bushy". If your hair has a coarse texture, try a straightening treatment or flat iron to smooth it out. This will decrease volume. You might also try this trick- slick your hair with gel close to the head and let it dry that way. When it's totally dry, break it up. You'll notice that you have less volume that way.
If you want to grow it out you are going to have a miserable grow out period, I'm not going to lie. Start with clips, or a headband as it grows out, and as it grows a little longer go for lots of layers to keep it as sleek as possible. Or, with extra thick hair, it's sometimes easier to go extra short- that also cuts the volume down. You could try a style like Halle Berry or Victoria Beckham. Very chic.
But I say keep growing it. Once it gets past your shoulders it will be easy. I honestly thing long hair can be easiest to maintain- you can skip days washing and go with a ponytail, you can go months without a cut, you don't need to style it every day. Get a stylist who will follow a "grow out strategy" for you. I hate to see mothers go for the bad new-mommy haircut. You don't have to have short hair just because you had a baby!
Well, I've gone on too long. If you live far from the places people recommend, just ask someone around town who has great looking hair where they go. I'm serious- strangers will not be at all offended by this. Best of luck!