I'd also caution that if you haven't had a dog before you should think about waiting until your 3 year old is somewhat older.
I will tell you that if I were you, I would take my sweet time, really get to know a breeder and her dogs, visit a couple times and get on the wait list for a breeding of a litter that is planned that the breeder thinks should be easy going, easy to train and biddable, not super high energy. There is no crystal ball, but a breeder who knows her dogs and how easy they are to live with will at least set you in the right direction. I would tell the breeder that you don't care which sex you end up with. She will know her puppies best, ask her to pick your puppy for you and give you the most easy going, not overly adventurous puppy, one that comes when called rather than running farther off to investigate etc. Temperament and energy level will be more important than sex.
I hope you will think a little about your preschooler and how well behaved, laid back he or she is. If you are very committed to puppy management and being religious about daily training and exercise for your dog for the first year or two, you should do fine with a Golden. If you aren't committed to obedience classes and daily training and exercise (not just a walk around the block, they need puppy playdates and lots of aerobic exercise) you may find that a Golden can be a handful in a busy household.
As suggested, use the search feature and do some research on this forum on the terms "land shark", "puppy biting", "puppy and kids" and "Puppy is driving me crazy". That way you will have full disclosure