That's what I was thinking - what was he doing in between his graduation from High School and his enllistment - except that that would have involved a separation of some 4+ years if he met Kay between 1938-1941 or so and 1945 .

Plus, I always had the impression - based on what, I'm not sure - that Mike and Kay were both students during the time of what we see of their courtship.

And.....based on their conversation at the wedding, it wouldn't appear as though Mike and Kay knew each other very long.