The timeline of Andi Mack is a strange one, but here's my best guess, based on logic. Now, this list is incomplete, because I'd like some help filling in the blanks.
1. 13-September 28th, 2016: Andi's birthday is September 28th, 2003. Since this episode is set on her birthday, it must be September 28th, adding to the school year already starting. Now, 13 years plus 2003 is 2016, which implies this is when the show begins.
2. Outside the Box-End of September 2016, as it picks up right from where 13 left off.
3. Shhh!-Early October 2016, as it takes place immediately after Outside the Box.
4. Dancing in the Dark-Weekend early in October 2016
5. It's Not About You-Still October 2016
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11.
12.
13. January 2017
14. Chinese New Year-February 2017, as Chinese New Year typically falls in February.
15. Every episode up to Cyrus' Bash Mitzvah is apparently in February.
16. The show seems to be in March 2017 by now.