You need to be at least using class objects for a project like this.
That is an absurd notion. And bad advice, especially for someone who clearly is very new to C++.

There is a time and a place for class objects. There is also a time and a place for structures and C-like object code. It is not necessary to use them. It is also not necessary to write object-oriented code.

C++ is a multi-paradigm language. It works just as well writing functional or imperative code as it does object-oriented code. (Though for OO code, it's actually not that good a language.)