We have had our grey Corky from a baby, But we did rehome a blue fronted amazon that was at that time around 12 years or so old that came with many issues. We have had her almost 2 years now.
Her name is Cricket and she has turned out to be a sweete and we have no regrets.
We used all the things that we learned for bringing up a grey when we rehomed Cricket and that is trust, kindnes, and lots of attention.
They take time to come around and each grey is differant in the time needed. If you like the TAG and have the time and the will than go for it.
This board has good people and they will help with any question you may have as you need to ask them