I got INxJ, which is close enough, I suppose.
Two things about the test, which is generally excellent:
1. Maybe another J/P question is needed
2. #6 might need a rewrite. Four isn't a big number of people, and it depends on who they are, too. I couldn't in good conscience say that either option was true for me because if those people I'm with are friends, I'm fine for a good while longer than if they're new to me. Of course, I could be biased because I am also socially anxious, which isn't quite the same thing as being introverted.