I don’t know if there was actually a story like this in National Geographic, but there was one about a city in the then USSR exactly like this, but I do question whether ages were changed to dodge the draft for a couple reasons. One is that the women were just as old as the men and two, late in WWII, Russia was also going through their revolution. Age didn’t make a difference. Some forums would grab kids and force them out on the front lines because (among other reasons), the enemy might be reluctant to shoot at children.
At that time there was no “draft” like we have. No registration for it, not checking of age. If you were an able bodied man, you could be taken in by an army of any particular type (and there were a lot of factions). While fighting in WWI was tough, it might actually be preferable to fighting in the Revolution. Those who fled to avoid fighting in WWI would easily be picked up and forced to serve, regardless of their age.
There are two scenes in Doctor Zhivago that people may remember that illustrate this. The first is when Yuri Zhivago is on his way home from the city to his family’s home in the country and men show up on horses and basically tell him they need a doctor and he’s coming with them. He doesn’t even have the chance to let his family know what is happening, he’s just taken and suddenly he’s a member of one of the armies, whether he is on their side or not.
Another is later, while he’s serving, when they’ve had to kill soldiers in another army to get through a field and when they’re riding through, they see the soldiers they’ve just killed are children.
I don’t know a lot about how Russia picked soldiers for WWI, but I seriously doubt they cared much about age. I’m sure some history buff can correct me on this if I’m wrong, but since records weren’t as clear then as now, I would think they’d just grab able bodied men without worrying too much about their age. I may be wrong on this point for soldiers in WWI, but considering the Revolution started just a few years later, I would think the recruiting methods wouldn’t be too different.