Good morning!
The short answer is go for ArcGIS Pro.
ArcMap is now entering what is known as "Mature Support" - see the link below:
ArcMap Life Cycle | Esri Support
ArcGIS Pro is Esri's premier desktop GIS Product and that is where all development and resources is being aimed at.
There are loads of excellent and free resources for you to get started with. Have a look at the ArcGIS Pro Resources page to access the free Tutorials:
ArcGIS Pro Resources | Tutorials, Documentation, Videos & More (esri.com)
And also have a look at the Esri Training website which contains many free training courses relating to ArcGIS Pro. Have a look here:
www.esri.com/training/Bookmark/P35SSUE32
(Notice I have ticked the "free" tick box!)
I hope this helps & have fun
ed
