creating an admin subdirectory

I am trying to create a separate subdomain for an administrator to edit their webpage, like admin.example.com

in cPanel, I created a subdirectory calle开发者_如何转开发d admin and it automatically created a root directory under /public_html/admin. I password protected the directory and it works great. It also brings up the password prompt when I go to example.com/admin. I know its because it created the /admin directory, but is there a way to only access it through admin.example.com? I might just be picky, but I'm curious.

I'm creating a very tiny cms for a client to update a few areas on his site and was wondering whats the best way for him to access the admin/edit page? Is a password protected example.com/admin directory ok? Or is a subdomain better? Or something else?

Both example.com/admin and admin.example.com are password protected. For a tiny CMS this security is enough.