Law is not a good career choice for an INFJ.
Here's a good article:
Law is NTs at the top of their game; not only your peers, the people you will spend incredibly long hours with for years and years, but the people who are you adversaries -- NTS at the top of their game who live to fuck you up.
There's no money in do-gooding. Unless you marry well or you are fine with having roommates the rest of your life and driving an old car, you can't work in the "Don't Polute!" side of environmental law, provided you could even find a job on that side of it. Environmental is about finding ways to allow industries to continue to emit, and proving why the insecticide on your fruits and vegetables should be allowed, etc.
Law is about winning, it's not about altruism or defending the innocent or any of that. Law is about winning for your client no matter whether they're innocent or guilty.