Brianlinkles, Congratulation with your new baby GW. GW Babies grow very fast, their beak will also never stop growing, it's like your finger nails, this is one of the reasons why you need wood toys and concrete perches in the catge so they GW can grind their beaks and nails.
There are many different sizes when it comes to a GW, The best way to get an idea on the size of your baby is to compare it to the Mother and Father, look at their feet.
Talking from expierence here, my Breeder alowed me to see my GW Neleno's Mom and Dad and the Mom was on the avg size where as the Dad was huge for a GW. They layed 2 eggs, one female and one male. My male GW Neleno was very much larger then his sister and has huge feet. I started to visit my Neleno on weekends when I could and work would allow. I live in MD and my Breeder lives in VA. I watched my baby grow and handled him at every visit. This way my Neleno knew me prior to me taking him home. I would advise you to dop the same if you can. At approx 3-4 months old, Neleno's feet were as big as my hands, his sister on the other hand was either avg to being on the small side. His sister was shipped to CA once weaned and My neleno lives here in MD with me. Today he is 5 years old and his weight is over 1700 grams, he is larger then some HY Macaws I know. He is a one person bird and I have done everything that I could to keep him social but this did not work for him.
I also have a 6 year old Male Eclectus who is a real sweetheart and goes to everyone. He is very social.
The bond that you are going to have with your GW will be like no other relationship you ever had with anyother animal. GW are known to form very strong bonds with their owner and the one they love. At first, your baby will want to keep their distance from you, this is the time they learn, (Can I trust this perosn) as time goes by, you will see a huge change in them and them yerning to be with you, cuddled, take showers with, eat with, go on trips or walks with you. These actions are all bonding times. I am very excited for you, your are going to have a blast with this new GW. Please post pictures if you can. Best of luck and continue to ask questions. Thanks for posting Joe