Sub domain & sub application(another web application under root)

Hi experts,
I want to create Admin panel for my website as http://admin.mywebsite.com.

For this purpose, I have created my sub-application at www.mywebsite.com/Admin/

Admin is a sub-directory under my root folder & I set it web application. Now, this is working as a different website & running fine if If I use www.mywebsite.com/admin.

Now, I want to use it from http://admin.mywebsite.com means I want to target sub domain admin.mywebsite.com to /Admin sub directory which is already a web application.

I read KB article "How to redirect a subdomain to a subdirectory" but this only works If I want to redirect to specific directory/sub directory in my root application (www.mywebsite.com).

I also tried to create a CName for www.mywebsite.com/admin but control panel doesn't allow this & raised an error "invalid destination".

Is there any way to target sub domain to my web application (under root directory).