An apprentice narrator could be appropriate for describing World War I mainly because he/she could be an impartial party on this issue.
The fact that this narrator is not inclined to any part, or doesn't have a vast experience, gives he/she the necessary objective point of view to narrate the facts in the most credible way.
He/she could make use of all specific details to support the narration of facts in a very well documented way, assuring therefore a very adjusted issue.