Ayy lmao! You're trying too hard, boy.
I never use Post Scriptum, fyi. But I will teach you something: both P.D. and P.S. are in latin. There are no rules in their usage, only cultural preferences.
That means you can use whatever you want, regardless the language you speak. Feel free to use it too, you can!
Man, I wish everybody could attend college like I do.