I'm sure it wasn't my first but I still remember it well. I was living in a flat in London. A Friday evening I think and the BBC cancelled TV programmes and played mournful music all evening. A bit OTT for a foreign head of state but it was the height of the cold war and JFK was our great white hope to keep the pesky Soviets in their place,
I remember the Democratic convention when JFK was nominated (I was 6 at the time and we got to stay up). I remember the Cuban Missile Crisis very well and, certainly the Kennedy Assassination (I was in 4th grade). My school principal came in class and told our teacher who was in shock. We got sent home a little later that day.
And especially, I remember seeing Jack Ruby shooting Lee Harvey Oswald live on tv. I normally got up early on Sunday morning to watch cartoons, (which weren't on because of the coverage) and remember the commotion, then they replayed it several times.
I was in the hallway for punishment in 3rd grade class when some sort of code came over the intercom. All the teachers came out of their classrooms and met in the hallway in front of me. They all started crying. The next week was like a sci-fi movie, the whole town shell shocked. JFK was a great man.
The 1984 famine crisis in the Horn of Africa, particularly in Somalia. I couldn't believe the TV images of starving babies and their mothers. That really impacted me. I thought I have everything I want as a child why can't they have at least Food... I believe that was a breakthrough for me to realize that there isn't really a God.
For me it was the JFK assassination as well. I was in Kindergarten, I was convinced the world was ending. The adults were crying, the calendar had only one more page, and everything on the TV was sad and dreary. I was SO relieved when mom put up a new calendar.