This is a common issue with young amazons. She's probably done hand-feeding or close to it and feeling the first real push of confidence and independence. The other issue is that amazons don't necessarily feel the need to get along with everyone in the house. In fact, most large parrots are selective about who they let pick them up. The more someone tries to befriend an amazon, the more the amazon pushes back. I think you first need to consider the expectation that everyone should be able to handle the bird equally. Honestly, this is unrealistic. Amazons are picky. That being said, I've had plenty of baby amazons that went through a real biting phase from about 4 months through maybe a year or a little after. They are busy at this age, learning to really fly, testing beak strength, throwing themselves into wrestling with their toys. This is an independent species anyway that doesn't usually like a whole lot of cuddling. Most of my amazons get a quick scratch when I walk by their cage and then I put them back down to play. If I try to push and make them accept all the love I would lavish onto my dog or cockatoo, I will get bit. At this point, let her be young and restless. Back off a little and keep interactions short. Always ask first before petting. I hold my finger a little out of bite range and ask my amazons if they want scratches. They figure out what it means fast. If they bow their head of fluff up their feathers a little bit, then it's probably a yes. If they grumble, ignore me, or turn their back to me, or flare their tail and flash their pupils, its probably a no. If the bird says no, I respect it. I might stand there and chat with them a little and then walk away. It's also helpful if you approach bearing gifts at random times with no expectation that the bird will allow scratches in exchange for the gift. Just hand her a piece of almond when you walk by the cage and don't even try to touch her. Give her an easy food toy like a paper cup with some small wood blocks inside and walk away. Only really try to pet her when the house is calm. That means no one is tense, has been yelling, no music or t.v. making noise, no noisy dishwasher, laundry machine, other pets and people are not nearby. Amazons will absolutely bite the person they are sitting on because they can't reach who they really want to bite (other people or pets). When the world is quiet and the bird is awake but looks a little sleepy, that is the time to approach an amazon and ask for a scratch. If she allows petting, don't get greedy. Give her a quick scratch and then move on with your day. If she is willing to step up, don't get greedy and ask for more. Praise her and put her back down...ideally with a treat.
One of my females put her beak through my thumb webbing when she was just shy of a year old. She was a sweet baby, then mostly hands off and defensive for a few months. Now, she's a great bird. I can even hold her close and give her a quick hug which a lot of amazons won't allow (even otherwise nice birds). This is a make or break time of life for amazons. If you play it wrong, biting can become a habit. If you do it right, she will probably grow out of the worst of it. Although, she may try to pair bond with someone and be generally grouchy toward everyone else as she approaches maturity in a few years. You really need to accept that the basic nature of the adult amazon is not super snuggly and generally she will have strong likes and dislikes and have her own personality. Trying to change her to meet your expectations probably won't work and may make things worse. It's easier if the human is the one that changes their behavior. While amazons are not necessarily great and meeting all of their owner's emotional needs, their independence allows them to roll through life's changes better than more codependent species like cockatoos. Treat her independence like it's a good thing. She's less likely to pluck out her feathers or scream for attention than cockatoos or macaws that allow more petting. The trade offs that come with owning an amazon should be embraced.
