I was in the sixth grade on this day in 1963. Our teacher was called outside the room and predictably we all started talking, only softly because he was fairly strict and no one wanted to be caught doing something wrong upon his return. But when he came back into the room, he didn't actually see us. His eyes looked strange, his face was grayed and he was subdued beyond anything we had ever seen from him. "The president has been shot", he said. "Our president has been shot." After all these years, I can still see his face as he said those words.
I don't remember much about the rest of the day. I think we were sent home early. I wasn't told until I got home that the president was dead. I knew what the word assassination meant, but I thought it only happened in history books.
For a fair read about why Kennedy had such an impact on so many read this article by Ken Ringle at the Washington Post: washingtonpost.com: The Day a Generation's Spirit Died.