A bit off-topic, but do you have clear recolection of other dreams at that age (or younger) or does this one just stand out because of its nature? I have a terrible long term memory and I can hardly recall everyday things from that long ago, much less one specific dream.
I recall all of my more eventful dreams from that age (and younger, but only back to 5 or 6), and that particular dream was definitely a welcomed shock to my young mind at the time.