Admirals in Star Trek tend to be middle-aged or elderly. Meanwhile, Kirk became a Captain in his early to mid 20's in the Kelvin-verse. I am trying to set a lower bound on the age at which one could reasonably be promoted to the rank of Admiral in Starfleet. Ideally, I would like to know the lowest age at which a Starfleet officer is known to have held the rank of Admiral. They do not need to appear on screen at this age as long as the age they had at the time of their promotion can be inferred from canon materials.
Rear Admirals, Vice Admirals, etc all count as "Admirals" for the purpose of this question. If they are referred to as "Admiral so-and-so", they're an Admiral.
The age of the actor portraying an Admiral can be used as a lower bound on the age of the Admiral themselves at the time of the portrayal, since humans tend to be healthier and have longer lifespans in Star Trek. But since this is a lower bound, an actor being young does not prove that their character is young. Feel free to include and consider actor age in your answers but do not depend exclusively on actor age as proof of youth. Actor age is irrelevant for portrayals of non-human characters or animated characters.
I am only concerned with chronological age, not biological age, so incidents of de-aging such as Admiral Jameson in "Too Short A Season" should be ignored.
All paramount-licensed films and television shows are considered canon.