I am an INTJ as well.
I actually took the official MBTI test twice (both times at work). First, in 1990 (at the age of 27). My results were INTJ (I=17; N=13; T=57; J=17). Then, in 1997 (at the age of 34). My results were INTJ (I=55; N=27; T=55; J=47).
I spent a lot of time reading about MBTI, particularly to understand the differences between Sensing and iNtuitive.