This annoyed me enough to make a account. it is very possible to make a small operating system, however it won't be like Windows or Linux where everything just works.
That being said it is very achievable to make a small OS that can do basic tasks see Serenity OS! If you want a OS that is competitive that will take a lot of time.
Here are some resources to get you started!
https://www.learn-c.org/
https://wiki.osdev.org/Main_Page