When Does "Star Trek: Short Treks: The Girl Who Made the Stars" (2019) Take Place?
"Short Treks: The Girl Who Made the Stars" is a science fiction animated short film written by Brandon Schultz that released December 12th, 2019. So when is "The Girl Who Made the Stars" set?
It takes place on the fictional Star Trek timeline roughly in the year:
We know this because during the quick prologue in the early 2030s AD, Mike Burnham tells Michael Burnham the ancient African folktale happened "1,000 centuries ago, in Africa..."

~97970 BC
We know this because during the quick prologue in the early 2030s AD, Mike Burnham tells Michael Burnham the ancient African folktale happened "1,000 centuries ago, in Africa..."
1,000 x 100 = 100,000
and
2030 - 100,000 = -97,970.
Additionally, there is a frame story in which Michael Burnham appears as a young child and is told the mythological story. According to "Star Trek: Discovery" season 1 episode 4 "The Butcher's Knife Cares Not for the Lamb's Cry" (2017), she was born in 2226 AD. She is clearly under 10-years-old but old enough to speak here and both of her parents appear so it must be sometime between 2229 AD and 2236 AD.
2226 + 3 = 2229
to
2226 + 10 = 2236.
It is the earliest chronological short film in the Star Trek universe and can be watched at its timeline point or as an extended flashback after "Star Trek: Discovery" (2017).