In-universe, there are a several female chief engineers that pre-date Lieutenant Commander MacDougal serving on the Enterprise-D under Captain Picard in 2364;
Lieutenant Commander Caitlan Barry served as Chief Engineer aboard the original USS Enterprise under Captain Pike sometime around 2254.
Number One twisted in midair and angled her body so she caromed off
the side wall of the null-G ball court using her right leg to push her
back toward the center. Chief Engineer Caitlin Barry had anticipated
the move and shot in front of the exec, body-blocking her away
from the ball. The collision of bodies sent them careening off in
opposite directions, but Caitlin had managed to backhand the ball,
slapping it toward the catch-trap goal in Number One’s end of the
court. As Number One somersaulted in the air to land with her feet
against the end wall under Caitlin’s goal, she saw the ball hurtle
straight through the catch trap and in. The Scoreboard honked and
racked up the three points for the chief engineer.
Star Trek: Vulcan's Glory
Commander Jett Reno was Chief Engineer of the USS Hiawatha sometime around 2257.
Commander Jett Reno was Chief Engineer of the U.S.S. Hiawatha when it
crash-landed on an asteroid. She transferred to the U.S.S. Discovery
after they were rescued.
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/ip4dA.png)
StarTrek.com - Jett Reno (Database Article)
Lieutenant Bexx was the Chief Engineer on the USS Hunley under Captain Linneus circa 2275.
Harriman moved through Hunley’s engine room, waiting anxiously for
word from Lieutenant Bexx. He paced back and forth behind the chief
engineer, trying not to disturb her as she worked at an
environmental-control console, but—“Anything?” he asked, stopping
beside her. From an intellectual standpoint, he understood the
requirements of command, and the need to allow people to do their
jobs, but however much time they had, he knew that it must be running
out quickly.
Star Trek: The Lost Era - Serpents Among the Ruins