I'm a Marvel comic book fan from Ireland.
I've posted the below against Uncanny X-Men 111 on this site but I thought I would reprint it here to give you an idea of my first marvel comic book experience:
Growing up in Ireland in the late 70s and a reader of such UK comics like the Beano and IPC's Buster, I first became aware of Marvel through the 60s Spider-man cartoon and then the Hulk TV series.
At some point, though, I became aware of American comics. These were exotic beasts, smaller than the UK comics and, wow, full colour. Also, instead of many stories in one issue, there was just one story all the way through.
I remember picking up this comic. My family were staying at a caravan park at my aunt's caravan. There wasn't a lot to do. I went to the park shop to see if they sold any comics. The only things they had were these little American comics and for some reason, I decided to pick up the above. I can't really recall why. Perhaps there weren't many comics available because I remember thinking the heroes in particular looked pretty peculiar - very different from Spidey or Hulk.
Anyway, I picked it up and made my way through it. I would love to tell you that it was an epiphany or something. But it wasn't. Truth be told, I didn't think much of it. I was probably 8 or 9 at the time and it was maybe aimed at an older audience. One thing did stick in my mind, though (really oddly) and that was that there was a big reveal at the end - Magneto on a splash page. I had no idea who Magneto was but, even at my young age, I could tell that the comic was signposting this as something important.
It was years until I picked an American marvel comic up again, though I did become more aware of the X-Men over time through reprints in Marvel UK's Rampage monthly. I started picking X-Men up pretty regularly from issue 166 and, when Rogue first turned up, well, I was sold.
So that's a pretty important comic book memory for me.