I am writing a story and have a flashback to two characters meeting, one from Shanghai (young woman), one from Tibet (old man). They're in an Anglophonic country and both immigrants. So I wanted a small taste of them speaking a common language (without regionalisms) politely on their first meeting but falling back into their host country's language fluidly, as she's educated in the language, and he's been there for decades.

The elderly man has just introduced himself in English but mentioned he's from China, and so she responds

Oh, nice to meet you Mr X! My name is Y! But here, people call me Z.

哇，很高興認識您，X先生！我叫Y. But here, people call me Z.

and later, when she mentions she's pregnant, (Edit) he congratulates her:

恭喜有喜了Z!

I had, like, one semester of Chinese fifteen years ago.

Does this sound natural, or does it sound textbook-ish? I want it to sound authentic, but have pretty much never had a Mandarin conversation (maybe once or twice, extremely limited greeting to friends' parents). Thanks a bunch!