hi...just a thought...make sure that she does not think you are rewarding the biting with a treat. This could easily happen. Use the food to attract her to toys but not to distract her when she is biting.
Sometimes, saying 'ouch' works. I think my bird went through a phase of biting to hear me say 'ouch' even though it was not a loud or excited sound. Because of the young age, you might try avioding the bite by keeping the fingers ways, trying not to react if she does bite, and not letting her at necklace, earings etc. You may have to take the jewelry off. She might be attracted by the bright colours or shiny metal. Remember, these could be swallowed if removed/chipped by the bird, as well as toxic, and/or cause of an obstruction.
It sounds like you should make a playstand/basket or a birdsafe necklace for when you are on the couch with her. I think in that case, she is looking for something to do and/or your attention.
Re: wobbling the hand if she bites - I have read to do that in a lot of places - I have also read some very respected behaviourists disagree with that approach - likely even more so with a young bird. You want your bird to think of your hand as a safe perch. A perch she will readily step onto when you are trying to remove her from your shoulder or when she is in or about to get into a dangerous situation.
You may also start wanting to wear longer thicker sleeves if this behaviour continues. They are good for hiding/protecting hands at times. BTW - it took a couple months but my bird did stop nipping/biting. And note, this phase could reappear at the 'terrible two's' and/or when the bird becomes hormonal in later years. Birds definitely teach you patients if nothing else. And always remember, not to take it personally. It was sometimes difficult when my bird's nipping started at 4yrs, but it was a phase and we got through it and he is even friendlier than before.
