I don't have a C++ background but Mongo has first class driver support in pretty much every major language out there. Its also far more flexible than traditional sql (for better or for worse) so you can get up and running quickly. Heres a link to the C++ docs on the mongo site:
docs.mongodb.org/ecosystem/drivers/cpp
While you're there, give a look around. Their documentation is quite good and very clear. I think you'll find it very easy to pick up.