If she is truly 2 years of age, I like to call this the "adolescent hormones".
My male Umbrella cockatoo baby, who is 2years old also, is just the same way. He is humping! He started his first humping when he was 10months old. Back when he was that young he didnt really know what he was doing. He'd fluff up and squat and do the tail wag on my arm
And now that he is 2, he still very young to be sexual mature, but he is indeed going through the baby/adolescent hormones. He doesnt try and seek me out to mate with me like Bokka my 15y.o male U2 or like Moby our foster 22+y.o U2 (which will scream for their mates, and get very territorial, etc), Opa is not like that and he doesnt seek me out to do "it". He does show some protectiveness of me, but nothing too serious as he is still very young and going through this "experiencing" stage.
I think its completely normal. But since this is a hen, I'd recommend to completely discourage all nesting behavior(without taking away any toys).
If you pet anything below her head/neck area, stop it immediatly. If you feed hr corn and pasta and carby and fatty foods, stop doing so immediatly. Starchy/fatty foods and petting below the neck helps a bird become sexually active at a very young age.
Typically greys and amazons and macaws and cockatoos shoudltn eb sexually mature or going through any real hormones until they are between 5-10 years of age. But a LOT start VERY young. I knew a blue and gold macaw male who was full blown cage territorial and displaying all nesting behaviors and aggression at 3 YEARS of age! His owner cuddled him, and snuggled him, and petted his bum, his tail and lower back all the time and everywhere else of his person. And all of that includign the very fatty/starchy food h ate (he ate a LOT of human food). Sadly his territorialness went to the owner and she got bit and attacked a lot (do to hormones(although she was his favorite)) and had to be rehomed... MANY rescue birds get into the rescue or sanctuary at 3-5years of age because they went through adolescence and sexual hormones very early