Following that statement, Michael Bay responded and so did director Jonathan Liebesman (read here), but now comes word from Bleeding Cool that the film's working title might actually just be Ninja Turtles, indicating that the movie might be losing the teenager aspect as well.
A source for the site said: It seems to be driven by marketing. Think of John Carter and how Disney wouldn’t allow for a title with either “Princess” or “Mars”.
One thing that might back up their claim is that the forums at Michael Bay's official site only list the movie as Ninja Turtles as well. You can see for yourself here.