I first remember it wasn't panties it was blood period pads that first interested me. And they were my cousins. I always even to this day look in garbage cans to see if I see pad wrappers or b***** pads.
Anyway it was female family we would visit from time to time and I'd always look in hamper in bathroom for fresh dirty panty. I was in my early teens. J still do these rituals to this day and I'm 48. I had quite a collection duffle bags full of clean, dirty panty or b***** pads.