Good question!

I think that my earliest memory of a President is from when I was 5 — actually, it was my 5th birthday.  That was the day that President Reagan was sworn into office for his 2nd term (January 20, 1985).  I don’t remember him being sworn in, but the Super Bowl also took place that day (Super Bowl XIX between the 49ers and Dolphins) and I clearly remember President Reagan doing the pre-game coin toss prior to the game.  The Super Bowl was at Stanford, but President Reagan did the coin toss via satellite from the White House. 

Another early Presidential memory would be from a year afterward when the Space Shuttle Challenger exploded.  I was in 2nd grade and there had been a big deal about the Challenger mission because Christa McAuliffe was becoming the first teacher in space.  A few classes from my school had gathered in our tiny library to watch the Space Shuttle lift off that morning and we were horrified when it exploded live.  I don’t know how my teacher handled that day, but I’m glad I wasn’t the one who had to explain what happened to a bunch of a little kids (although I did have to do that on 9/11 and that wasn’t fun).  Anyway, I have clear memories of watching President Reagan give his “slipped the surly bonds of Earth and touched the face of God” speech to that nation that evening.

UPDATE:  The Reagan Foundation has the video of President Reagan’s coin toss at Super Bowl XIX on YouTube.