We haven't seen the actual evaluations, so I think it's hard for us to know what was asked and what was concluded in the psych evaluations.
If the psych staff were told, here's someone of indeterminate age but good reason to consider she's over 18...that doesn't mean they're going to expect to find an 18 yr old mind inside that 18 yr old body. People of 18 can have a mental age of 11 .... were the psych staff tasked to find out which it really was? Or were they only tasked with diagnosing and helping N as a patient who was brought to them, which is what would normally be the case?
I haven't seen anything yet in the limited medical information that's leaked out that 'proves' to me beyond doubt that the age on the birth certificate was either incorrect or more than one or two years out. So it doesn't seem logical to me to assume that 1) the age was wrong, and 2)knowing that her age was wrong, she managed to pull off a massive con on the adoption agency, the Barnetts, on the doctors who did the bone scans, on the psych staff, and so on.
What about the teeth being 'adult' and yet still losing deciduous teeth at the legal age of 23 or 24?
If I ignore everything from the Barnetts that might be biased and not verified by a 3rd party, then what am I left with? For me, I can't see anything that conclusively says the child wasn't a child.
I am willing to change my mind if medical evidence comes out that is a proper medical report, and I would give that evidence greater importance than anything else as there's less chance of outside manipulation or bias in actual scans -- though it is still possible to have bias in interpretation, but with numerous experts checking each other on those, then it should be possible imho to get closer to a realistic age range for the individual.
There are experts out there who work in 'aging' individuals from ancient civilizations...they don't use psych reports or stories from the family, they just go on what they know of biological aging. So I see the rest of it as unimportant faff and not compelling at all.