When a defendant is charged with a crime which constitutes a violation of RCW 9A.64.020
or chapter 9.68
, 9.68A, or 9A.44
RCW, and the alleged victim of the crime is a person under the age of eighteen years, neither the defendant nor the prosecuting attorney may agree to extend the originally scheduled trial date unless the court within its discretion finds that there are substantial and compelling reasons for a continuance of the trial date and that the benefit of the postponement outweighs the detriment to the victim. The court may consider the testimony of lay witnesses and of expert witnesses, if available, regarding the impact of the continuance on the victim.