When you create the variable in the startup scene, you need to create it as false instead of true. Like this:
*create mourning_song false
Long-ish explanation
You can *create variables at any value that you want (either in the startup scene or using the *temp command elsewhere.) This goes for true/false, numerical values, and even the retrievable "text" variables.
However, whatever they are when you first *create/*temp them will be their default state until you change it with a *set command.
So your mourning_song variable is reading as true by default because that’s how you created it; meaning your *set true command in the prologue doesn’t change anything. That’s also why your stats page is always displaying it. Because it’s never set false.
I saw your other post and I would guess that you’re having the same problem with the *temp values as well, but it’s hard to say for sure without seeing more of the code or knowing what kind of errors your encountering.
Anyway, ‘mourning song’ is a pretty epic variable name! And I hope this helps!