Good start - for inspiration, you can check out Drew DeVault's (
https://drewdevault.com) "bunnix", a Unix-like OS implemented in his own "Hare" language in about two weeks:
https://git.sr.ht/~sircmpwn/bunnix
Some suggestions for further projects:
* multi-core support
* portability, e.g. to an ARM or RISC-V machine (assuming you started on x86)
* networking