Personally, I would have gone with an Ambassador, Excelsior, Constellation, or Miranda class over the Connie in that case. They are still not top of the line new ships, but they are somewhat newer, and closer to what the cadets may encounter on their assignments. They could (while assigned to the ship) take a course of classes similar to a History Class in the Holodeck over the operation of older vessels like the Connie.
Here is an example of what I would use for those purposes. The vessel itself is 85 years old: CD is the Commissioned Date, it was Decommissioned 41 years later, then pulled out of mothballs after 40 years for an emergency situation. Had a minor refit performed earlier in the year to give it the EMH and Armor. USS-Reliant-A.pdf - Google Drive