If you're really serious about this, stevenup7002, then I suggest you grab the source for one of the OSs out there for which the source is freely available. If you do some searching on the net, you'll probably be able to find a relatively simple OS (when compared to things like Windows and Linux). A quick search turned up
this (I didn't download the sources, but then, I'm not trying to write an OS). If you can't make sense of it, you're not ready to write an OS.
If you are still wanting to write an OS, you'll need to know assembly. OS development is one of the areas where a knowledge of assembly is still necessary. You'll also need to learn the APIs for Windows, Linux, and MacOS if you intend to emulate them. For MacOS, you'll be doing more than emulating another OS; you'll need to emulate the Mac hardware as well (most specifically, the CPU, though there will be other elements as well).
I hope you understand now why some of us made fun of you. Writing an OS is not a trivial undertaking. You're not the first to post some bold thread about writing an OS, and the other people who did so got mocked, too. If you want to avoid that, write a bunch of the code, get it mostly working, and then show it to us.