The decision to be a dog owner depends on a few factors. First you need to know if everyone in your family agrees to the idea. Second you should evaluate if you or your family has the time and space to dedicate to the new family member. Lastly, having a dog has significant costs, you’ll have to pay for the veterinary, it’s food, medications and eventual medical conditions.
There are three main factors to consider when choosing a dog. It’s size, personality and energy level.
If you live in an apartment maybe you should opt for smaller dog breeds. If you have children a more docile temperament should be preferable. If you intend to run with your dog a high energy level dog might be considered.
You can look for the characteristics you intend to prioritize and search for breeds that best fits your needs.
It is my personal opinion that you should always prefer to adopt from a shelter, and the reasons are a few.
The first is that you can literally save a dog’s life by adopting it, because there are so many abandoned dogs some shelters are so overcrowded that they are forced to put down unadopted dogs. So if you adopt one you can be removing it from the death row.
Another reason is that it’s much cheaper to adopt, most of the time it’s free. And in some countries you can even have discounts on veterinary fees.
Last but not least, some dog breeders have some very bad practices. Some use consanguineous breeding that produces genetically weaker dogs and potentiates congenital diseases. Others simply kill newborn dogs that have any deficiencies. If a dog isn't bought when he is a puppy chances are that he will eventually be abandoned or killed. So by not buying from them you remove the monetary incentive to those atrocities.
A good dog to be near children or babies is a docile dog, with not too high energy levels and that isn’t prone to be envious.