Is it worth beginning C++ or stick to Blueprints?

This is the number 1 reason to learn the basics of C++. Basic algorithms becomes a hideous spaghetti nightmare very rapidly in Blueprint.

At a very minimum I would learn how to create Blueprint function libraries so you can avoid that horror show, even if you build your entire game framework in Blueprints.

https://wiki.unrealengine.com/Blueprint_Function_Library,_Create_Your_Own_to_Share_With_Others