Glitter, I actually think that adopting an older dog is an excellent choice in your circumstance. Trying to take care of both a puppy and a baby is enough to try the patience of a saint ! At least this way, the dog should already be house trained, and not bouncing all over everything, and doing all the energetic things that a puppy would constantly be up to. Puppy's mean well, but they " just want to have fun" as the song goes, and it would be easy for a puppy to crash in to a toddler and hurt them.
An older dog will be a lot more settled. The main thing is to get one that is sociable with children, and small enough to live in an apartment, as well as large enough to be a good guard dog. Also, a dog with short hair is better than a long haired dog, since you will have a young one grabbing ahold of the dogs hair if it is long. I think you will be happy with your dog once you find the right one, so good luck with this !