Quote from JJ:
"It was fun to use the Romulans the way we did. The fact that they hadn't seen them for so many years, that it so immediately breaks - for anyone who knows - the rules of Trek. We start the movie with Romulans crossing paths with Starfleet and jump right in breaking the rules, which I think is kind of fun."
So there it is. It is obvious that JJ never intended to follow the rules or continuity of Star Trek from the beginning. So they can tell whatever story they want. Chekov may be older than Kirk in this version of Star Trek. Who knows? And if he is 12 years younger than Kirk, as he should be, then he's probably a genius of Hawkinian proportions to actually outrank a cadet whose 12 yrs older than he is. Either way, this movie will not fit into established Star Trek history in any way shape or form. It is indeed a BSG-style rebbot of Star Trek and a completely different universe from anything that has come before.