That is good advice.
Practicing law is like going fishing. The 80/20 rule is at work. 20 percent of the best fisherman catch 80 percent of the fish and do quite well, the other 80 percent of fisherman struggle to get by on the remaining 20 percent of the fish. It's the same in law. There are too many lawyers chasing a very limited pool of legal fees. The top 20 percent of lawyers make 80 percent of the money, the rest struggle to get by on the scraps. About half of new lawyers fail and leave the practice of law within three years.
Today, in order to have a reasonable chance of finding a good job in law, it is vitally important to go to a top law school, and to do very well in school. If you go to a top 10 national school, graduate in the top half of your class, and do a second string law review, you will be competitive for jobs at top tier firms and very competitive at second tier firms. If you go to an average law school, you'll need to graduate as one of the top 10 students in your class and be an editor of the primary law review at the school in order to be considered for a job at a top tier law firm. If you graduate in the middle of your class at an average school, you will be lucky to find any legal job.
I'd say, go to a top 10 school, or Tulane (maybe a top 25 school), or do not go to law school.
Many "admiralty" lawyers only spend a very small percentage ( maybe 10 percent) of their time on admiralty and maritime related work. The best chance to do a significant amount of "admiralty" work, is to work for one of the insurance defense firms that specializes in defending seamen's injury claims. Your job will be to prevent injured seamen and their families from receiving compensation, or at least limiting that compensation. That is soul sucking work.
Whether you decide to go to law school or not, I suggest sailing on your license for a couple years first. Prior to starting law school build up your research, analysis, and writing skills. That's what being a lawyer is all about.