To open files in CC 2017 by default, you need to set file associations, either in the operating system, or in Bridge. (Bridge CC 2017 isn't installed by default, by you can install it using the CC desktop app)
In Bridge, go to Preferences > File type associations, and set NEFs to open in Photoshop CC 2017.
In CS6, the D7100 files should open, provided you have version 7.4 or later of the Camera raw plugin.
The latest (and last) version for CS6 is 9.1.1.
I do not know what Adobe software you have installed or had installed on your machine. I have Photoshop CS2 and all Creative Cloud versions of Photoshop installed. So I have an Adobe Bridge that opens a very old ACR and Photoshop CS2, Have Adobe Bridge CS6 that Opens ACR 9.1.1 and Photoshop CS6, have Adobe Bridge CC which opens ACR 9.8 and Photoshop CC 2014, Have Adobe Bridge CC 2015 that opens ACR 9.8 and Photoshop CC 2015.5 and have Adobe Bridge CC 2017 which opens ACR 9.8 and Photoshop CC 2017.
Make sure that You are using Adobe Bridge CC 2017, Photoshop CC 2017 and ARC 9.8. Also check your Windows registry key Photoshop.exe and that the commands to open and edit are pointing to C:\Programs Files\Adobe|Adobe Photoshop CC 2017\Photoshop.exe
File extension Associations can change what version of Photoshop opens...............
Thank you so much, Per Berntsen, it was totally that. I had totally forgot about those preferences ! Now it works perfectly. Thank you JJMack too. Have you guys a perfect day !