(just adding a couple of things to Stéphane's correction)

First Class

Je m'appelle Sophia, je suis chinoise, j'habite à Shenzhen. Je suis assistante export.

Remarks/explanations:

In French, we capitalize the first letter of a word after a period. However, you do not capitalize after a comma (unless the word needs to be capitalized, like Sophia, or Shenzhen). You also need to put a space after the punctuation.

Also, we capitalize proper nouns, like names of people (Sophia, Pierre, Stéphane...) and countries, regions or cities (Chine, France, Shenzhen, Ningxia...), but not the names of languages or nationalities. In English, you would write Chinese (with a big C), but in French (en français), we just write "chinois" or "chinoise". Examples:

La Chine est un très beau pays.

Sophia est chinoise, elle habite en Chine.

Je suis français, j'habite en France.

First Class

Je m'appelle Sophia,Je suis Chinoise,J'habite à shenzhen.Je suis assistante export.