Come on Eileen / At this moment, you mean everything.

Commander Eileen Collins began military pilot training for the Air Force in 1978, the same year that NASA opened the Shuttle program to women. She later became the first woman pilot of a Space Shuttle on the first flight of the joint Russian-American Shuttle-Mir program, and now the first woman to command a Shuttle mission.

(These facts excerpted from Cmdr. Collins' official bio on NASA's site)

And this isn't some run-of-the-mill shuttle flight, either: it's the first since the Columbia disintegrated over Texas and it's safe to say the future of NASA was riding on Discovery's back.

Speaking of back, Cmdr. Collins performed a unique maneuver: in a feat of aerial acrobatics reported around the world,

Collins took manual control of Discovery and pitched around in a backflip about 600 feet below the ISS [International Space Staion].

While a feat of orbital acrobatics, the backflip – known as the Rendezvous Pitch Maneuver (RPM) – was pivotal highlight of Discovery’s flight. During the maneuver, Collins slowly flipped Discovery in a circle to give the Expedition 11 crew a clear view of the heat-resistant tiles lining its underside.

(quoted from Space.com's article)

The LA Times has a nice video of the maneuver.