Sophie darling, you don't convert anyone's time any more.
You use the time they give you. If they forget to say, then assume they are Eastern, and if all your posts show as Pacific time, ADD 3 hours to their time. Or don't score them - they are supposed to say what their local time is.
Ballet posted at 3 pm her time, and Kathyh3 posted at 5:51 her time, so Ballet clearly posted earlier and is the winner.
Whether Ballet knows she won is a whole different mob of meerkats.