Since I am planning to buy a new MacBook Pro (2017) and currently working on a Windows 10-device on a ASP.NET MVC (Not ASP.NET Core MVC) project for my internship, I was won
As you've correctly surmised, it's not possible to build ASP.NET MVC projects on the Mac that aren't based on .NET Core or Mono. So if your project is currently targetting ASP.NET on .NET Framework 4.x, the you'll either have to stay on Windows:
Or you can convert your application over to Mono or .NET Core, depending on your dependencies that may be relatively easy, or very hard or anywhere in between.
You could also decide to use Visual Studio Team Services to build your code on a Windows Hosted agent and edit the sources on yoru mac, you'd have to forego the ability to compile or run your code locally.
You can also decide to "rent" a virtual machine in Azure (maybe your have MSDN credits you could use for this purpose?) and remote desktop to that machine to work on your project.