Something that many people might forget is that there is another factor outside of the exact time you order. Not everyone who ordered in the "first batch" will be getting "Preparing for ship" at the exact same time.
This is because ultimately everyone lives in different regions, which are involved in separate bulk shipments. These bulk shipments can take longer to be received and then processed depending on the area. For example, if one such bulk shipments were to be in Kentucky (for example), they might actually not move to "Preparing for ship" until tomorrow due to time of day, etc, while one of the west coast might still be working.
Likely what we are seeing with the people who are getting charged and their status changes is because they all live closest to the place where the first bulk shipment landed. These shipments are strategic to allow the fastest spread of packages across areas, so they are usually major shipping hubs.
tldr; you will know when you are getting yours soon, no need to fear just because others are getting notified