When you receive a shipping confirmation email with tracking, please allow at least 1 full business day for the tracking information to update. That notification is triggered when the package is 'ready to ship', not necessarily when it's shipped. Depending on timing, the carrier may not pick up your package and initially scan it for a full business day (ie - not on the weekends).
If it's been more than 2 business days, feel free to reach out to customer service and we can see if we can find out more information for you.