Hello and welcome!! I highly recommend you check out Birdman666's posts and threads about macaws. Read every single post in the macaw forum.
Kings cages are great. They're sturdy and last a long time. What are you planning on feeding your new Greenwing? Parrots do well on a varied diet, including fresh fruits and veggies, and many people will add pellets as a base to this. Seeds can be offered but should not be used as their primary source of nutrition. Nuts of different kinds can be used as treats and for training.
At this age when you get your baby, you should allow them to settle in and work on building trust. Don't handle her right away, especially if there is lunging or defensive behavior. Wait for her to settle, and offer her treats through the bars of the cage. Eventually you'll want to work on bite-pressure training, target training, recall, and of course, socialization with other people and animals is very important for young macaws.