A puppy is a LOT of work!
It's probably in your best interest to wait until you have real time to help it grow up and become a family dog that you can be proud of. Puppies are similar to babies in a lot of ways, they need to be put out every couple of hours, after every time they eat, every time they wake up and after every time that you play with them. They need to be walked (exercise), and socialized. I know people will say that there are other ways to raise puppies and that it's really not that hard, I agree to a certain extent, however these are basic guidelines that will most often end up with you having a family dog that you are proud of.
Another important thing to note, it's important that the dogs personality fit your lifestyle. Dependant on things like how active you are, where you live (no sense getting a border collie when you are living in an apartment, you will end up with a neurotic dog, unless you have hours to exercise it a ,and surely your house guests will wonder why they are being herded... it's what the dog is meant to do) That is just one example I know, but again that said, choosing a dog that fits your family is SO important.
That all said. I will admit that I ended up getting a puppy about 4 days before we found out we were expecting and lord did I ever question myself about that one! I was fortunate that my OH took over EVERYTHING to do with the puppy, feeding, socializing, potty training, walking, while I was dealing with being sick all the time. At this point my pup is just 3 months old and I have been VERY lucky (have also done some dog training before) and he is 99% potty trained, has a reliable recall (come), sits and lays on command as well as does his job as a retriever very well (was purchased as a bird dog). He is no where near done tho and I still fourtunately have another six months to dedicate to him and his growth. My fingers are crossed. I could not imagine having to deal with all of this while having a baby here too. Again it can be done, but it will take a LOT of planning and thought.
This all is probably way more than anyone wants to know but, I know that a lot of people always say that "I want my baby and puppy to grow up together" I just really want people to think it through. Puppies grow into dogs and if they don't receive proper attention growing up you could end up with a dog you aren't so proud of.