another backcourt question

[missinglink]

Frosh girls. A1 is advancing the ball by walking speed dribble from her right backcourt. She is angling to her left diagonally and crosses the division line in the middle of the center circle. She picks up her dribble on the division line and the ball's last bounce was in frontcourt; right foot is in front court, left foot is in backcourt and neither foot has been made pivot. A1 passes to A2 in backcourt to her left. I called backcourt violation as I judged ball had achieved frontcourt status based on its last bounce and three point principle application ceased upon cessation of advance on dribble. My partner said I got it wrong based upon 3 point principle and I am not so sure now.