If you have the Tier 2 Starters Guide that covers Visual Studio 2015, then you're all set because you will be using the same C++ code anyway and there is no template for Visual Studio 2017 yet.
I believe that, for AppGameKit developing purposes, Visual Studio 2017 is just a different editor with perhaps a slightly faster compiler. But the code you'll be using as an AppGameKit developer will be exactly the same because the AppGameKit commands should not depend on the Visual Studio version, just the templates. And, like I said, there is no windows 2017 template yet.
For these reasons, I would definitely stick to the Visual Studio 2015 IDE for now.
You can (re)download Visual Studio 2015:
https://my.visualstudio.com/downloads
Just make sure that you uninstall Visual Studio 2017 first (in case you have it installed). I did this yesterday and now I'm doing fine with Visual Studio 2015 with the 2015 template.
Hope that helps.
AppGameKit 2017.04.24 (Steam)
Windows 7 Professional 64bit, Service Pack 1
Dell Precision T7400:
Intel Xeon CPU E5405 @ 2.00GHz (2 processors)
16GB RAM
Nvidia GeForce GTX 560 Ti
Samsung SSD 850 EVO 250GB and SanDisk SDSSDXPS960G