3 year old Green Cheek Conure is aggressive?

I need to downshift. So I got him (gender unknown) from an exclusively bird pet store. In my opinion, looking back, I might've rushed into it. No one else in my family wanted a bird, and it was just me (I was still in middle school, and am now in high school) to take care of him. At first, he was a great pet. He loved me, and would even fall asleep on my shoulder. He was mildly trained, he could step onto or off of surfaces by command, and could understand "no" and that me wobbling my arm a little meant no as well. However, even then he hated everyone but me. I think that means he imprinted on me, but I'm still not entirely sure, especially now.

Maybe a year, year and a half in, he got very nippy--I assumed it was his teething/growing up stage. I tried to train him/keep him nice, but it didn't work. I, who was a relatively young girl without help from anyone else, would occasionally get mad and scared of my little guy. I never hit him, never touched him in any harmful way. What I did was shake. If he bit me, he would latch on and screech a battle-cry at me. The only way I could get him off me was to shake him off. I think this probably was the start to him beginning to hate me too. He started getting unbearably loud. I found that if he was away from people, he would be more quiet. Even if he was a room away, where he could hear but not see us, he would behave a little better. But my family still didn't like the sound, and though this has stopped, there was a period where people would tap/bang on the cage to quiet him.

I know this, what I have done and what my family has done, isn't good. Its terrible. And now my bird hates everyone. I'm leaving for college soon, like a year-ish, and I'm trying to see what I should do and what option I have.

I know this is long, but I had to give background info. Now, my bird bites all fingers, and he only likes being on my leg and occasionally arm/shoulder, though he hates my hands and bites me eventually if he's on my leg. He attacks everyone else. The weird thing is he's still attached to me. If I get from a chair, he'll follow me around the room, and will screech if I leave.

Here's my options that I see:

-get rid of him (I don't know how to do that, and have never given a pet away before....I can see the benefits, and sometimes I want to give him away, but I also feel such guilt. I don't think I'm a good owner though)

-keep him, and find a way to bring him to college

-give him to a family member (I don't know how they'd do this since they've never fed, cleaned, played with, or trained with this bird, and have no desire to)

-somehow fix this behavior problem

- any others?

Thanks, I really need advice.

I would suggest you try to pinpoint the circumstances during which he starts biting. He doesn't "hate" you, but he's probably afraid for some reason. Maybe there's a lot of noise and activity around him, or maybe some of your other family members scare him. Every bird will be afraid of your hand if you use it in a threatening way, such as holding it over the bird's head. Once you've figured out the circumstances during which he bites, eliminate those circumstances. No fair responding with "all the time" or "I don't know," since that's just a cop-out. A modicum of screeching is normal and healthy. Again, figure out if it's abnormal and what is causing it. No bird is going to be quiet 100% of the time.

Considering your circumstances (age, living situation, future) I recommend that you find the bird a new home and that you not wait until just before you leave for college. You'll want time to feel what you'll feel about the birds absence and get used to to living life without him so you can start college with a clear mind.

You have many options, and it is all determined by how much you’re willing to put into him. If you have 2 hours a day to spend training with him, I think you can get a great bird out of him. These 2 hours should be broken down throughout the day in about 15/20 min sessions or just time out of the cage on a play stand with some foraging toys.
His behavior is normal in this type of situation, you acknowledge and take responsibly for his behavior, so if this was me, I would keep him, and work with him and see the wonderful life I could provide for him. You care enough to ask, and care enough to see there is a problem. The only way he’s going to get better with you is if you invest the time in him. But where to start?
#1 put him on a training diet. (if he’s on open feed, move him to meals so there are points in the day he’s hungry. Find out what his favorite treats are (the thing he’ll always eat first) and only use them during training).
#2 clicker training (the clicker is a “bridge” between the instant he does something right, and the time we get him the treat) To introduce the clicker you should be able to hand feed him treats- through the cage at first until he’s ready to come out without biting/nipping. The very first session should just simply “click” instantly hand him a treat. After a few reps, click- if he’s looking for a treat, he’s made the connection.
#3 start bond building games. I highly recommend starting with target training, get him use to a stand or coming out of his cage, and then working on things like spin, wave ect.
#4 intoduce a perch to use rather than your hands until you've built a bond where he won't nip at hands. hand hatred takes time, but can be fixed.
please feel free to message me and I would love to offer any advice or guidance to help build a bond with him.

does he enjoy foraging? if you place his food in foraging toys, that will help entertain him while in his cage so help distract him from screaming. FYI: In the wild a bird will spend 80% of their waking hours looking for food, that doesn't always mean they find it- yet we just give them open feed all the time. which means they get bored, and bored bird will scream for attention.

IMO, you leaving for college is the most important thing to get figured out because what you'll need to do if you somehow can take the bird with you is different than what you'll need to do if the bird can't go.