Arms behind early or late?

I'm new to the site and trying to go from a mostly arms swing to more of a body driven swing. I'm doing a waist high backswing with a focus on the pelvic punch move, and while I make solid contact, my arms seem to be behind where they should be at shaft parallel and at impact. I'm trying not to do much with my arms but maybe I am letting them get too far behind me in the backswing so they never catch up? Or is it that I need to move my arms more in the downswing? This also may be the least of my faults so any advice on priorities/drills to work on is much appreciated.

Thanks,
Kevin