My cousin has five children, all under the age of 7.
She just had her fifth child and her border collie puppy is about 7 months now.
She got him whilst she was pregnant (and whilst she had 3 little one's to look after, as well as a toddler!)
Puppy's are hard work and they will stress you out a little

My cousin broke down whilst she was pregnant because of the puppy, he was chewing all sorts in her house! My mum just calmed her down and told her it's to be expected and that he'll stop soon. I've had 3 puppy's in my life myself as well as a 9 month old dog once too, we have a rottweiler puppy at the moment. I'd definitely recommend a border collie or a labrador, or any type of family dog like that. They're both very intelligent dogs and very friendly, but of course it all goes down to how they are brought up, and I'm sure growing up with your family the puppy will be a big ball of loveliness!
I have a Labrador Cross Border Collie, A full breed Border Collie, A Rottweiler puppy.
I've also owned an American Pitbull cross Mastiff. Such a lovely bunch of dogs all of them have been to me, a pain in the bum sometimes though!

xxx