Welcome to the forum. I have an Indian Ringneck as well, but my boy is only three months old. He's my first bird. What I have discovered is that it takes a while for these birds to trust you. They require daily interaction and attention, and even "handling" to remain tame. Do you know your bird's history? Was he with a breeder or pet shop until you got him?
Another thing I noticed is that if you can get him to another room, out of sight of his cage, you will probably notice far less aggression. It is very natural for a male IRN to be aggressive while he is on his cage. Three days is not a very long time to establish trust with this bird. I would suggest opening his cage door so he can come out if he wants to, but just sit nearby talking softly to him. Also, don't do long periods of eye contact with him at first, that makes them nervous. In fact, when I first got mine, I could do just about anything in his cage as long as I wasn't looking at him. Talking softly to him whenever you are near, really helps. For some reason, soft talk is very calming for them.
You can start clicker training him to move towards you and get used to taking treats from you, and it won't be long before he will want to be out and be near you. Many of them don't like being touched, and receiving head scratches like a lot of birds do, but every bird is different. Just take your time and you'll figure out what works for the both of you.
Welcome again!
