Congratulations! You will be extremely happy whether it is a girl or a boy. Boys tend to think Dad is the coolest dude in the world. Girls tend to think he is the king of the world. You can't go wrong either way. Raising kids is the greatest hobby in the world.
I had a girl and a boy. Now, as grandkids are in the picture, I have a grandson with a granddaughter on the way. Life is good!
One word of advice... Prepare for all the great outdoor stuff whether it is a girl or boy, but if it is a girl, be sure to brush up on tea party etiquette.