There was nothing specific that did it.
I've always loved things that are bigger or smaller than they should be; from an extremely young age watching cartoons and playing fairies on the playground.
I think it was then a logical leap as I grew older and became aware of size difference as a genre, not just a kink, that my brain went "Oh hey yeah this is really good"
There is no chance of me remembering what the first true size dif content I was exposed to was, but an artist that I've been a fan of the longest in the genre would be Ken-Sample / Cougr who I recommend highly



