Timeout During Throw-In??

[CDurham]

The situation I had was I had a throw-in on the baseline for Team A. I had the ball in my hand and as soon as I raised it I heard "Time Out" from Team B Coach. Clearly it was when I had the ball to administer the throw-in. However, my motion continued and the ball bounced to Player A. He grabbed the ball and that is when I blew my whistle to grant the Time-out. I didn't get any heat from Team A's coach, but wondered if I handled it correctly