I was 7, and I remember riding my bike that morning with my brother and running into the newspaper delivery man (The Columbian, no doubt) at the end of our street outside of Battle Ground, sitting in his car staring off into space.
He said something like, "Did you see the mountain?" at which point, we saw what he was looking at and looked back and saw the ash cloud rising over the mountain.
Mom and Dad put us in the car, and we went on a drive to try get closer to get a better look for most of the day. Although I cant remember where it is we ended up, I do remember some spectacular views.
My dad worked for the Federal Highway Administration and for years after was involved in designing new roads for the forest service and the monument. I did a lot of bragging that my dad had a red zone pass. He was also a pretty good tour guide of the area because of that, and we took many out of town relatives and guests up and around the mountain for years afterword.
I got to watch the area transform after the blast as part of those tours and also learned some of the science behind the plant succession on pumice plain and lahar as a botany major at the University of Washington.
I have no doubt these experiences helped shape my lifelong interest in nature and profession in natural sciences.