Each Provider can customize their First Booking Date. If, for example the provider doesn't want to take booking any earlier that 3 weeks in advance, but the business takes bookings 4 weeks in advance, the provider can do set that:
Manage > Providers > General Settings
In the above example, clients cannot booking same day, and they can only book up to 2 weeks in advance.
The following image shows the client view if the client wants to book 3 weeks in advance: