Sorry for the giant comment O.O I just wanted to list all the birds I think are great first birds for older people who are willing to do a lot of research and be prepared. I think green chicks are really cute, but I love these birds :)
If you have any questions on birds you can ask me, I've been studying birds for fun since I was a kid and I have a huge amount of information. I also play with my friends large parrots pretty often, and have a Galah cockatoo.
I know you already know this, but for anyone else considering it
Please don't get one of the large white cockatoos if you don't have any large bird experience. They are insanely adorable the first few years, then as they come into the teenage years and start getting hormonal they will probably try to bite, and it hurts
a lot. if you show fear to them, such as pulling away, they will dominate your relationship with them and become something you might fear. Many cockatoos end up at animal shelters because of this :(
The Galah/rose breasted cockatoo and Goffins cockatoo are more independent and a better alternative.
The
Galah is very intelligent, can learn to talk, and as all cockatoos very good at learning tricks. They can be happy sitting in the room with you, but still love to be played with and getting pets.
They don't chew as much and are quieter then most cockatoos, but can still be fairly loud.

Goffins cockatoo
Although it's more independent then the larger white cockatoos, the Goffins, also known as the Tanimbar Corella, still demands a lot of attention. They are also very smart, and will eventually learn to get out of there cage so make sure theres a good latch, or even a lock.
Alexandrine parakeets, as well as
Indian ringneck parakeets are wonderful. They don't like to be pet as much as cockatoos, but love learning tricks and are both(Especially the Alexandrine) intelligent and can learn to talk.
-Both birds should be handled everyday(as all birds should have) to keep them tame.
-only the adult male has the ring on the neck
The Alexandrine is about 20" long with it's large tail. Also has a blue mutation.
The Indian ringneck Parakeet is much smaller, and comes in several different color mutations, they're also cheaper- about $200-$300 compared to the Alexandrine at around $600.

The normal morph is the green.
Sun Conures
fairly demanding and love to be with there owners. They tend to travel good if it means they get to be with there person lol
a little more demanding then the green cheek, but very playful, can learn a couple words, and often travels pretty god if it's with it's person.

Pionus
These are pretty quite birds, and are playful but gentle, and tend to not bite. They are intelligent like a amazon(similar in appearance too) but only learn a few words.
There are a few different species