Here's a screencap of that claim:
Here's some of NASA's bio on Mae Jemison:
Notice that the NASA site says, "Mae Jeminson is a...former NASA astronaut."
Notice that the Faceboob post says, "...the first black woman to become an astronaut for NASA...."
The headline is right; Jeanette Epps will be the first black woman astronaut to go to ISS.
"Layers and layers of fact checkers."