New commenter Joe was kind enough to drop some hilarious history here which does not speak well for the shield maiden trope.
During the late stages of the [American Civil] War, the town of LaGrange, Georgia, had an armed all-female militia unit which drilled with weapons and which mustered in the street apparently ready to fight when the Federals arrived. The Yank in command, a gentleman and a diplomat, sent a messenger under a white flag to tell them that their homes would not be burned and that (as I recall) “they could surely do more damage with their eyes than with their old squirrel-rifles”.) Reassured, they stood down. LaGrange was not burned, but in a touch suitable for the worst of novels, the Federal in command later married one of the members of the “Nancy Harts” girl militia unit.
Otherwise: They would have been slaughtered. The Union force was strong enough that the Confederate cavalry fled them; according to a link provided by Dalrock.
In mid-April 1865 Major General James H. Wilson led a Union raid on west Georgia. As the Union troops approached LaGrange from West Point, the local Confederate cavalrymen fled, and the Nancy Harts stepped in to protect the town.
…which was accomplished by entreating the Union soldiers to spare the town, and then surrendering to the strong handsome Union soldiers; even unto the mattress.