Bad timing! Right call (I think)

[Jake80]

Ground ball between 1st and 2nd. Second baseman gloves the ball but pitcher doesn't cover 1st. Race to the bag and fielder barely beats the batter/runner to the bag. I call the out. Big train wreck. Nothing malicious. Fielder drops the ball. I reverse the call to safe. Damn! That was bad timing. However I believe I did get the call right according to Jaksa/Roder page 26-27. Can someone please confirm that I made the proper call or correct my interpretation? Thanks.