Pd or any graphical environment for audio is a good place to start; better than code in fact which in many ways represents the flow in a more indirect way. If you feel fairly confident in the area of DSP algorithms then I would say moving on to text based programming is the next step. Putting the Juce library before the language it uses is a mistake though. It might even be a mistake to put C++ before C.
Learn the basics of C syntax. I recommend skimming through a tutorial on C by Mark Virtue for Virtual Traning Company. Do this but don't worry about C-specific things too much like C-style strings and #include "stdio.h." Just get the core language under your belt and move on to C++.
C++ is a huge and scary language but if you have focused on a particular USE for it (like Juce) it can help you prioritize and make it much more pleasant. To learn C++ I used many resources: VTC, Lynda.com, pluralsight.com, various books MIT Open CourseWare etc but none of them stuck with me really as a routine. Now I'm pursusing certification and getting free training for it via cppinstitute.com. cppinstitute.com is very heavy and in-depth so I keep referring to this: https://www.youtube.com/watch?v=3fwKlU9AwSY&list=PLfVsf4Bjg79Cu5MYkyJ-u4SyQmMhFeC1C
I have build a few plugins in Juce now. proof!: http://jeff-russ.github.io/AdlibBlaster/
Just BE PERSISTANT AS FUCK and there is no way it won't happen for you! :)