Goal Kick with Opponents in the Penalty Area

I’m an assistant coach with a GU14 team. We were awarded a goal kick and my keeper setup the ball in our goal area very quickly. At this time there were players from both teams (opposing and ours) in the penalty area. I wanted my goalkeeper to do a quick restart because we had an advantage at midfield. But she waited until the penalty area was cleared of all players before taking the kick. My question is:

1. Could my goalkeeper execute a goal kick with players from the opposing team standing in our penalty area to gain an advantage for our team?

USSF answer (January 19, 2010):
Correct procedure for the goal kick requires that all opposing players be outside the penalty area when the kick is taken.

We suppose that your player could take the kick with opponents in the penalty area, but doing so might cause problems for all sides, including the referee and assistant referees. If the ball is played/contacted by anyone inside the penalty area, the goal kick must be retaken because the ball is not yet in play (unlike the free kick where it is in play the moment it is kicked and moved) If the ball leaves the penalty area, is therefore in play, and then goes to an opponent who, at the time the goal kick was taken, was in the penalty area, play should continue (no matter where the opponent has moved to by that time)