I/E isn't as much about whether you are "outgoing" or "gregarious", etc. It's really more about whether you:
* Process things internally/externally * Get energy from being with people or find being with people "draining"
I'm also an I who has learned socially acceptable things like public speaking, participating in group discussions, etc. but a couple of hours in such a group and I'm exhausted while my E wife is energized.