11 years before the launch of the Enterprise Bee, Kirk meets Antonia while horse back riding.KIRK: "I took this horse out for a ride eleven years ago ...on a spring day, ...like this. If I'm right, this is the day I met Antonia."
9 years before the launch of the Enterprise Bee, Kirk cooks eggs for Antonia to soften the news that Kirk was returning to Starfleet.
7 years before the launch of the Enterprise Bee, Kirk's dog Butler dies.
In order for Kirk to return to Starfleet, he would have first have had to of left Starfleet. Following the Enterprise A's change of command to a new Captain, retirement would seem to make sense for Kirk. It not clear how much time elapsed between Kirk leaving Starfleet and his meeting Antonia.
Certainly enough time for the Enterprise A to have a couple of five year missions under another Captain (or two), be permanently decommissioned, have a year or few go by and then have the name Enterprise assigned to a brand new ship.
Uhura message from Starfleet mentioned decommission, Kirk final log suggests otherwise.
from TUC
Captain's log, U.S.S. Enterprise, stardate 9529.1.
This is the final cruise of the Starship Enterprise under my command.
This ship and her history will shortly become the care of another crew.
To them and their posterity will we commit our future.
They will continue the voyages we have begun ...![]()
The dates don't necessarily tally precisely because someone in the Nexus might not have a clear sense of when now is. Kirk must have retired for a period after the second 5 year mission I suppose before returning to his training assignment in TWoK. This adds an additional period of time (at least 2 years) between the end of that mission and TWoK so I think 2273 for TMP is closer to correct rather than the 2278 suggested by the actual Stardate.
The second 5-year mission would then finish in 2278 and Kirk can retire after another period of administration bores him to submission. Assuming 2 years of admin is enough to give him itchy feet as in TMP, this would give us a 4-year period of retirement.
Still, the Enterprise A was a relatively new ship, fitted with new equipment. It seems silly that she would be retired after such a short period of active service compared to the 30+ years of the original, especially when Kirk indicates clearly that a new senior crew would be taking over.