True. I'm old school as well, and certainly would not let my 12-year old run around Beijing, Wuhan, or any other Chinese city without a 100% trusted "guardian." And I would find it difficult to put 100% of my trust in anybody that didn't come on personal recommendation from friend or relative. I'm on the fence as to whether the 23-years old and the young woman-ness factors are a plus or a minus. If you go forward with this, you'll have to put a lot of faith in this person.

I can see the aunt/uncle's point-of-view, as this is completely out of the norm for a 12-year old Chinese child, regardless of apparent maturity level. How can you be sure that they won't nix the arrangement entirely, since they have temporary physical custody?