Angie Kirby was a Starfleet officer, with the rank of ensign, that served aboard the Defiant in the 2370s.
In 2374, she participated on an attack on a Dominion sensor array in the Argolis Cluster. Afterwards, she found out it difficult to believe that Julian Bashir had helmed the Defiant after Lieutenant Haj was injured. (DS9: "Behind the Lines")
In 2373, the Defiant entered the atmosphere of a planet (later named "Gaia"), and discovered a settlement of their descendants from an alternate timeline. In the alternate timeline, the crew of the Defiant were sent back in time 200 years, and stuck on the planet.
In that alternate timeline, Angie Kirby and Doctor Bashir married and procreated to a point where the planet was "crawling with Bashirs" by the time the Defiant made its visit. However, when the Defiant failed to go back in time and fulfill it's "destiny", the colony presumably ceased to/never existed. (DS9: "Children of Time")