You misunderstood what I said.
The Great War influenced the USN's funds for warships. To man them, they needed officers. The classes in the Academy at the time all graduated early. IIRC, the class of 1917 in January, the class of 1917 in mid 1917, the class of 1919 in early 1918, and the class of 1920 later that year. I'd have to dig out boxes from the attic to get the exact dates, but that is roughly correct. None the less, their class remained the class of 19xx with the xx being the expected year of graduation.