I would say that you are going about your process of discovery badly. First, before you want to make a game with characters and objects, you need to learn how to use classes and functions. To me your question of whether a certain process will take too much resources, indicates your problems lie in planning too many steps without focusing on a given aspect adequately. It is important that you test a particular aspect with the simplest case possible, in order to ensure you fully grasp necessary concepts like variable scope. Many times people want to skip ahead to things like transformation matrices, without first seriously asking themselves why they are using classes in the first place. People are taught in school and everywhere else that classes are necessary, and that they are in fact what c++ is all about. This is actually false. I did not have anyone tell me this, I discovered it on my own. Classes make thinks slower, more complicated and more tedious. Unless you are smarter than me and can use them in a manner I do not understand.
OK then, if we should not use classes, then how do you make a program? A program is actually only functions and variables. The thing classes introduce is neither of these things. Classes control, or they were intended to control the scope of functions and variables together as a single local group. If this sounds confusing, its because it is confusing. Functions already had local scope for any variables declared within a function, while all variables declared outside functions (generally in header file) have global scope. The reason this was important in the 80s and 90s, was the limited amounts of RAM computers had then made it possible to run out of memory. This is still an issue, however, it is a different situation. The problem lies with a thing called the stack. It has a limited memory, I think 1Mb. It is essentially a form of fast processer cache. If more memory is returned from a function than this 1MB limit allows, it produces a stack overflow, and the program crashes. This was not really a problem in the 80s and 90s, because games were less sophisticated. Anyway got lost on a tangent there, and yes I am aware that nearly every human being on the planet writes their software using classes, so everyone who thinks I’m wrong can save their time and just consider the possibility that you don’t know everything.