Zachary Quinto, who plays Spock, is 39.
Zoe Saldana, who plays Uhura, is 38
John Cho, who plays Sulu, is 44.
Chris Pine, who plays Kirk, is 36.
Anton Yelchin, who played Chekhov, was 27 when he died earlier this year.
Simon Pegg, who plays Scotty, is 46
Karl Urban, who plays McCoy, is 44
As of the release of the Star Trek (2009) film, these actors were around 32, 31, 37, 29, 20, 39 and 37 respectively. The youngest actor, Yelchin, was was still not a teenager, and the next youngest was a whole decade away from being a teen of any description.
For comparison, the original series was about 50 years ago. So:
- Leonard Nimoy, who played Spock, was 34.
Nichelle Nichols, who played Uhura, was 33.
George Takei, who played Sulu, was 29.
William Shatner, who played Kirk, was 35.
Walter Koenig, who played Chekhov, was 30.
James Doohan, who played Scotty, was 46
DeForest Kelley, who played McCoy, was 46
Are the ages of the characters as of Star Trek (2009) reasonable? Well, most of the characters are cadets in Starfleet Academy (albeit perhaps graduating ones):
“We have a crisis situation. We have received a distress call from
Vulcan. Further details will be forthcoming, but as of this moment you
are no longer cadets, you are Starfleet officers. I’m afraid that for
this year’s class the usual graduation ceremonies will have to be
postponed. Your official certifications will be placed in your files,
which may be inspected at your leisure—once you are in space. I
apologize in advance for any omissions. All complaints due to
oversights will be duly reviewed. In any event, you will not have time
to monitor their progress. Listen for your assignments. If you do not
hear your name called, check with the nearest senior officer.”
Star Trek (2009)
So for them to be 37, say, actually seems a bit high. Chekhov is certainly on the low end, but he’s supposed to be a prodigy even in-universe:
McCoy wasn’t quite ready to accede to the strategy. “Now wait a
goddamn minute! How old’s this kid?”
“I am seventeen.” Chekov sat up straighter in his seat. “How old are
Star Trek (2009)
It’s possible that people’s perceptions of the relative age of characters in Star Trek are being influenced by the phenomenon of Dawson Casting, in which older actors play younger characters, with high school students often being played by actors in their late twenties.