I think its their lawyer who keeps postponing it, for one simple reason: The entire case hinges on the testimony of the daughter, who was very young and influenced by the father to make up the charges. I think they're trying to give the kid a chance to grow up enough to understand the situation her father had her create, and to come clean on the witness stand. If the kid has been trained by daddy to lie about this without really understanding it, and the trial starts, Mercedes is finished.