So reviewing my childhood photo album, I noticed that i could identify which of my tritype fixes I was being in a determinate moment (using VI, then remembering). I think I can pinpoint when exactly each of the enneagram fixes happened or first appeared. They say a person's personality becomes "fixed" or practically set at the age of 5 years. You mature from there onwards, but the core of your being has been established. So I guess that's when your enneagram fixes are set.
Now for socionics... I believe it is genetic and you are your type since you are born. Pretty sure of this, so if you have any contradictory evidence, please post it.
Thoughts?