I have four that stand out quite well... but I don't know which is the earliest, nor exactly how old I was.
1. Riding my tricycle out to the road to watch the school bus go by. I was 4 when I started Kindergarten. I was not in school when this occurred so at most I was 4 but most likely even younger.
2. Watching a 'silver' plane flying to the east. I believe this is an earlier memory. I know this is a very early memory because of the lack of a 'pasture' I explain in the next memory.
3. Getting 'stuck' in an irrigated field by my house... wearing field boots. My Dad drove by and saw me stuck in the mud and had to come rescue me. This field was later converted to a pasture but my Dad was never able to remember the exact year... by the time I was 5 it was definitely a pasture so I was younger than 5.
4. I believe my earliest memory... your story is what brought these memories to mind and especially this one. Wetting the bed. I remember my Dad getting me out of bed and standing me in front of a small electric heater in the living room, (very small house).. to dry off. My Mom said I was not a bed wetter for long. Most likely I was 2, (younger?), and certainly not over 3.
