Your store will be active from the moment it is created.
Until the time the root directory of the store is created some of the features will not be active this includes email, FTP,Add new page. The time taken to create the root directory is 4 hours. In the meantime you can work on other parts of the store.
*Payments made using the PayPal echeck service are not reflected until the echeck has cleared which can take up to 2 weeks.