For me it was by watching Junjou Romantica in Youtube when I was 16. I mistook Misaki with a girl and I thought it was shoujo. So, it was a real shock for me, I didn't even know yaoi existed in general and I was super innocent even at that age. Anyways, at first I felt disgusted (I grew up in a quite homophibic family), but after that shock I became curious and kept watching. Now I only read yaoi lol.
After I stumbled across my first one, it didn’t take much convincing. Well.. I didn’t like my very first one per se, but the ones I discovered after that had super intriguing stories and such adorable relationships reply