My memory plays tricks with me because I have a very strong memory of walking into the living room and both my older brothers were watching Wrestlemania 7 and I had no idea what wrestling was and I sat down and watched it with them.
But I also have a memory of kids trading the cards and stickers at school and me not knowing what they were. I specifically remember someone having an Ultimate Warrior card and being amazed by it.
I think both those things probably happened at around the same time, probably the cards first, not giving it much thought afterwards and then walking in on my brothers, putting it together that this was what those cards were for and going from there. Specifically the match I walked in on was Nasty Boys vs Hart Foundation, but I do seem to remember The Undertaker's match really being the one that caught by attention.