In real life Pine is 9 years older than Yelchin, so it's not that much of a stretch.
Remember, we aren't seeing these actors play their characters in the same timeframe throughout the whole movie. We have no idea how much time passes from the first time we see them till the movie ends.
In otherwords, I think we need to see how they explain Chekov in the new movie. I'm betting that one of the first things brought up to JJ and the writers by their advisors was the whole Chekov/Kahn thing.
You people have ruined "Star Trek The Next Generation" for me. You are absolutely the most insufferable group of jackasses I have ever had the misfortune of spending an extended period of time with. I hope you all f@*#! die. - Stewie after spending the day with the TNG cast.