I've been learning C++ for a little while (about 3 months) and I haven't bothered to research the prerequisites. Should I learn design patterns like OOP before or after?
oop is not a design pattern.
i wouldnt bother learning about design patterns yet. if you're following a book or course just carry on doing that, and some of your own small coding projects.
oop is more like a mental approach, like top down or bottom up. Its a system we use to help us decide where to put code and how to organise and name data.
it will become more apparent the more you code in c++ or other oo language.
Not every coder is capable of understanding this subject, let alone implementing it. my advice (c++since '84) is to let it come naturally over time.
I thought I'd never get OOP but just keep reading up on it, don't use it if it's overkill though. Once you keep reading up on it, you should know when's the right time to use it.