I assume you're implying they meant she's Chinese.

From GP's text I assumed she's not Chinese but for whatever reason (parents worked there, she was adopted as a grown-ish kid, something else) she spent most of her formative years there.

Maybe we're both wrong but on its face what GP wrote doesn't strike as odd at all to me.

she could be chinese, but given how many chinese live in america, stating that she grew up in china is a helpful distinction.