I was about five years old. I remember that all of my siblings were there which is a rare occurrence because two of them are so much older than I am. My dad was buying my brother and I tomahawks at a shop on a Native American Reservation in Arizona. It was our "outwest trip". It's one of the few things I can remember from during my parent's devours. I don't know where the tomahawk is now.
There were no extraordinary circumstances that I can think of.
I think I was pretty similar to who I am now just shorter and a little more ignorant. Just as interested in blunt objects. I was not changed.
Five is a little old for a first memory. Was purchasing a tomahawk something you looked forward to? Was this an object you were fixated on? That might have made the memory special to you. One thing that makes things stand out in my mind is how new the experience is, or how much excitement/anticipation I felt surrounding the event. A combination of these could be what made this special for you.