I want to get everyone in a habit of emailing in their request and issues first. Once this has been established I would then like to introduce the portal to them 3 months from now. If this isn't possible I will have to look into other solutions.
It's certainly possible to never have users login to the portal. Accounts are automatically created the first time they email in, and you an turn off the email notifications for the account creation as well as edit your templates to not include a link to the ticket itself. That should keep your portal "hidden" until you're ready to unveil it.
Thanks, @Andyfor pitching in.
As @Andypointed out, you can remove all references to your portal by removing the links in the notification emails sent to the users. You can configure this under Admin-> Email notifications-> Requester Notifications section.
Cheers!