overrunning first base and look back rule

[shipwreck]

I thought that I had this all figured out and now am not sure. When a ruuner overruns first base and lets say turns to her right, and THEN the ball is returned to the pitcher in the circle, is she committed to first or does the pitcher have to have the ball in the circle and THEN the runner overrun first, turn right to be committed to first? I just am not sure of the timing. Here is play we had that doesn't go completely like this play but here goes anyway. Batter hits a line drive to right field, fielder throws to first in an attempt to get a force out but runner beats the throw. She overruns first, turns to her right and starts to walk back to first, THEN the ball goes back to the pitcher in the circle. Before the runner returns to first, she takes off for second. My partner calls dead ball and runner out for look back violation. Is this correct? Does walking back to first and then ball going in the circle commit her to first? Thanks, Dave