I don't know if I should have posted this earlier, but with help from Knight of Time, I figured out something earlier this year.

So, I have had two 3DS systems at use for years because I have been playing Chocobo Tales in the multiplayer mode with some friends who live nearby, and it seems 0276-2159-0898 is my friend code for the other system. My Mii for the this secondary system is called mjt2.