Hi Nuiloa,
I've been wanting for days to reply on this thread but I was getting ready for a trip and had to get a zillion things done. But now I am where I was going to and have time to write.
Like you, I'm single and an introvert. I forget the exact numbers but I think among early retirees in general and here on E-R the percentage of INTJs (I'm one too) is something like ten times what it is in the general population. I'm planning to join the "garden, read, knit, noodle around on the computer and play with the cats" brigade when I retire, with an occasional genealogy research trip thrown in for variety. I really think going to church on Sunday mornings and choir practice one night a week will be just about enough social interaction for me, but if not I can always take a class, or volunteer for something, or ask the vicar over for tea.