It was mid 2008. I was a Senior in high school and dating a boy who was really into fantasy. He introduced me to Mistborn. I started reading out of girlfriendlyness obligation. I mosied through it VERY slowly; took months before I finished the first one. I am SO glad I finished it a month before we broke up, or I may have never gotten sucked into the Cosmere fandom.
My now ex and I had pretty much every class together for the rest of the year. I think it annoyed him that I was now part of this tiny little following and I would read WoA during several of our classes together. It bugged him. I think I finished that book because I loved to see how irritated he got.
Then I read HoA. I have never had my mind blown by a book before. This was the most amazing piece of literature I'd ever experienced (and it was totally an experience). However, I was too nervous to delve into the Cosmere at that point for fear that my love of the series might be tainted by anything less amazing than what I had previously read.
My freshman year of college I got married to my husband and we attended a university dinner together. It was an awards ceremony for students who were being featured in the university publication of creative works. They gave out prizes and I won a copy of Elantris. I was unemployed and had no internet so, despite my previous feelings of wanting that first experience to remained untouched, I read Elantris. It was good. But I wasn't sold on the Cosmere as a whole yet.
Flash forward to 2012, I borrowed my sister's copy of AoL, finally ready to delve into a new Mistborn adventure. If I remember right it took me 2 months and 3 tries to make it through the first 20 pages until you reach the hook. Aaah! Once I finished that first chapter, I could not pit it down.
My husband saw how much I LOVED Alloy so he bought me WoK. He handed it to me with excitement and my face fell. I was really scared about trying to read this book. I'd never read anything this ambitious or large. I had a 10 month old at the time and didn't feel capable of doing it.
I read it in less than a month.
Since then I have been totally and fully invested in the Cosmere. It took awhile to be convinced of the Cosmere as a whole, but his individual stories were what got me to finally commit.