Hi,
Size really isn’t a good indication because in general parrots are full size once they have all of their feathers. They will fill out some, but not significantly. And with a conure, there isn’t an obvious increase in size. Since your new bird’s eye color has already changed to the lighter color, she is over a year old but she could be 1, 10 or 20. The eye color isn’t a good indicator of age after the first year. As with most parrots, there is no way to really guess a bird’s age once they have their mature colors, other than a very few exceptions. For example, the Blue Crown Conure’s feet gradually change from pink to an eventual really bright orange, which can take 20+ years. And some birds defy the norm – some African Greys and some Macaws have been known to keep the darker eye color of a juvenile bird. So just enjoy your new bird and let her be whatever age you decide! Fortunately most parrots do not exhibit signs of aging like dogs & cats, and while some develop age related issues, others seem to never age regardless of how old they are.
Thank you for asking Lafeber,
Brenda