is it possible to write a operating system and utilize it with the latest programming language <GO>. i come up with a ideal logic, but the problem is im not sure do i have to code the API by my self or get existing ones if possible to acquire.

Are you asking if it's possible to write an OS in Go? The answer would be no, as Go's runtime relies on the OS for many things (ex: memory allocations). If you're asking if you could interact with an OS using Go, the answer is a definite yes. You could write your OS' API in C, and expose these methods to Go, allowing you to interact with the OS using Go. Best of luck!