I'm in college and I've been an INTJ since 6th grade. Your type can change, but it really depends on the person. I personally thought the description was spot-on, but of course it could just be confirmation bias.
I'm not sure about that since I did flit back and forth between INTJ and INFJ in middle school. It was only when my sense of logic and reasoning grew in high school that I consistently was INTJ.
The descriptions used are so vague they can apply to anyone.
I'm an INTP too