This is not as easy a question as you may think. You see, my wife was born in mainland China but is American. She is also Canadian. My sister-in-law was born in Taiwan and is also American, although none of the rest of her family is. I have a good friend who was born in India, who is also American. I had a co-worker from Ghana who was also American. I had a coworker from Haiti who was also American (I think...I'm not actually sure about him, but since his kids were born in the USA, I know for sure that they are American at least). I had a coworker whose parents were from Mexico. He was American. I knew this kid in high school who dressed a little differently, but otherwise looked the same as everyone else in my rural town. Swedish. Another such girl. French. In college there was a kid who I was shocked to learn was actually from Hong Kong.
So what's the point, right? The point is you can't tell if someone is American just by their ethnicity. You need to be more precise.
Ironically, not all Chinese even look similar, contrary to what you might have been led to believe. China is a big place with a lot of people and various ethnic groups. When you think of what Chinese look like, you probably think of Han Chinese. Not everyone in China is Han, however.
So I imagine your question is, does she look Han Chinese or not? To me, sure. Why not? In animated style, people look all different types of ways.
But you know, even if she is Han Chinese, she could still be American. They are two different issues, which where the discrepancy lies.
This is especially a salient point (or it really should be) in the USA. Even those who came here to New England on the Mayflower were immigrants, after all.