There is nothing to set this up automatically for you but you can manage everything with roles, though in this use case scenario you would be needing a lot of roles.
You can create a page and set the edit permissions and create child page permissions to include a role that the user is in. Now the user can edit the page and create any number of pages beneath that page, so the first page is a starting node for what can be a whole tree of pages the user can create and edit. You could either put the mentor in the same role so he can edit too, or you can use a separate role for the mentor but give that role the same permissions.
You could potentially create a UseRegisteredEventHandler to create a role and setup the first page for each user.
Hope it helps,