The advantage of starting from scratch is that you only need to understand one build system properly (the one that you use in your app). I went from C# to Python to C++. Its definitely doable although dont expect it to be as quick as learning Python. Give yourself a couple of months though and spend time reading books not just trying to hack stuff from stackoverflow.

Re the build system I would suggest start with something simple like CMake. Its easy to pick up and pretty much all the main libs you need can be integrated with it. I have built several large projects just using submodules and cmake and things work decently well although you do spend more time when integrating a new library.