Start with Blueprint and when you feel comfortable with it and if you have any interest in C++ start to combine C++ and Blueprint to get the best of both worlds. Blueprint is capable of nearly everything but you will be looking at an endless mess of wires at times that could have easily been done in C++ but that is the sacrifice many are willing to make to stay away from the complexity of C++.
If you are making a multiplayer game with a dedicated server you will need some C++ sooner or later.