Congrats Aww! How old is your first again? I have two that are 4 1/2 years apart and it has worked out great! Older daughter loves to play the little mom, she is a big help. BTW...I just have to say that your avatar frightens me immensely!!
Anyhow, congratulations, you know the drill though, get all the sleep you can now, if your first will let you, you will need it later!!