In "The Mote in God's Eye" (Larry Niven and Jerry Pournelle) there is a good reason for using very young officers for starship command.
I recall the Captain who met the moties being inexperianced and he messed up. What was the reason for a young Captain?
I liked the reboot. They may have screwed up the old storyline or timeline but I expect some great movies despite JJ
Still waiting for ringworld and Louey wu on the screen.
And let's not forget "Ender's Game" that had kids leading entire battle fleets. Seems age-ism works both ways...