OKAY, ARGUMENT TIME:
Me and my friend spent an hour arguing over this in school, so:
YES OR NO, MOCKINGJAY KATNISS WOULD BE AN AMAZING WEAPON IN WORLD WAR ONE?
Yes
No
She insisted no, but I swear to god she would be an amazing weapon.
In mockingjay she gets arrows that explode and catch fire, and in catching fire (movie), she fires arrows pretty damn far into the forcefield over head.
She could just shoot explosive arrows from over the western front and absolutely shred.
What about tanks?
Tanks were first used in the Battle of the Somme on July first 1916, and were used by allied forces. As long as she.comes in before this time than she's alright, otherwise she still isn't guaranteed to be killed by one.
Germans only had 18 tanks. She could also blow them up or put them on fire.
Machine guns
Machine guns were first used by the Germans, many lined across the active trenches on the qestern front. This could be seen as a problem. But,
One machine gun took 6 men to run at this time. If her or anyone else took out one man then they'd have to get a replacement before they could continue, in which time the rest could be shot down.
Or she could blow it up.
What happens when she runs out of arrows?
Okay, this is actually a good point.
Most people in Britain who weren't farmers, miners, railway owners or children under the age of 12, worked in factories making supplies for the war effort.
Just have some of them making more arrows. Yes, they probably wouldn't be flammable or explosive, bout still good enough.
Rationing.
Well yes, when german u-boats started to cut off British food supplies from America and by 1918, Britain only had 6 weeks of food left, katniss is a hunter from 12, the poorest of districts. She knows what to do when she has little food left, and how to get more of it.
Britain also had a steady supply of fish and ground root vegetables. She could live on that.
America joined the war in 1917, so by chance with extra help, and the fact that Germanys allies, Italy and Austro-Hungary did shit all, the war may have ended slightly quicker.
Guns?
I'm not sure, but I kind of feel that katnisses armor would be strong enough to survive even a few blows.
A downside though, is that it doesn't matter how much fancy armor or weapons katniss had, the conditions of the trenches and the Western front were poor. She'd still be treated like a soldier, and could still easily die when they were told to go over the top, (run across 100-200m of land whilst Germans shoot at you), due to bullets, cold, bomb craters or mud. I think she is more likely to die of the conditions than actual war.