Bridget,
You have gotten good advice, I'll add my two cents.
Decide if you want a puppy or an older dog. Puppies are cute and full of potential and lots of work. An older dog may already have some training and you will have a better idea of how big it will get and what kind of temperment it has.
Find a dog with a hunting background. If it has hunt test titles, JH, SH, MH, SR, WR, MHR, GMHR, HR, HRCH, GRHRCH, or field champions, FC, AFC, NFC, NAFC, in the pedigree that shows trainability and other desirable traits. The lack of these titles does not make for a bad dog. A dog with only CH, show champion, in pedigree does not mean the dog won't be a good hunter, you just don't know.
Color is your preference. There are no differences between the colors in ability or temperment. Male or female (dog or bitch) is personal preference too. The females will tend to be smaller. Both have their pro's and con's. I reccomend you spay/neuter either one.
Don't be in a big hurry. Find the right dog and breeder for you. It is hard to walk away from a litter of puppies and not buy one. So, don't go just to window shop. Buying a puppy/dog close to home gives you a resource when you have questions. They can also be a good resource for training questions. You may also want to try and locate a near by retriever club. They can be a good resource for puppies/dogs too.
Training is very important. And, easier than many people realize. Consistency is the key. Dogs are creatures of habit. If you/Blake can teach the dog to obey sit, here and heal, all the time, it will be better trained than 90% of the rest of the dogs you will ever encounter.
A tired dog is a good dog. I guess the same can be said for boys too! Realize a puppy/young dog will have lots of energy. They will need daily exercise, including days with rain, sleet and snow. this can include walks, swimming or just someone throwing a bumper in the backyard for 20 minutes. Tennis balls should be avoided. Dogs love them but, they can get lodged in the throat.
That was longer than I thought it would be.
Good luck finding the right dog for you and Blake,
Tom