Memory in youth is active and easily impressible in old age it is comparatively callous to new impressions but still retains vividly those of earlier years.
Your body actually reminds you about your age and your injuries - the body has a stronger memory than your mind.
Over the years Woodstock got glorified and romanticised and became the event that symbolised Utopia. It's the last page of our collective memory of the age of innocence. Then things turned ugly and would never be the same again.