Hi. I'm also writing my own operating system. I once tried adding all of the flashy things to my OS before I had a full understanding of Assembly and techniques I could use, etc etc.
Although it's great that you are keen to write a graphics driver, I recommend writing some code for doing stuff like putting text on the screen and converting integers to strings or something like that before attempting.

Try getting a basic OS with a bootloader, kernel and shell and a simple 256-bit color graphics program up and running first.

Just my opinion based on past experiences...

Thanks,
Phillid