My two cents, which hasn't changed, so pardon me for the guys who have heard me say this time and time again.
The commercial diving industry is terrible right now for those graduating from school. It has been for the last couple of years. Gone are the days when right out of school you could make $20 bucks per hour. There are 10'ish + schools that are pumping 20-30 students out every single month. Not counting this month, or the month before, or the month before, and so on and so on and so on.... there were about 2300 Commercial Divers out of work. These are the guys like me who have 10+ years experience and have proven themselves in the industry. How hard do you think someone right out of dive school is going to have finding a job?
Ok, but a good hurricane season could really change all of that. Pre-Katrina a diver right out of school going to the Gulf of Mexica was making $8/hour. Two weeks after Katrina a diver right out of school was making $20/hour. I pray daily that a hurricane wipes out the gulf. I could use the income.
So, lets say you want to risk the 20k+ (and it's actually closer to 30k now). Do you want/have a nice family life with wife, kids, dog, etc? I'd bet your first divorce attorney's fees that you can't be an active commercial diver and stay married. I know literally hundreds of Commercial Divers, yet I know less than 5 that are happily married and not an alcoholic. It's no coincidence that if you look in the phone book Diver is right next to Divorce.
But, lets say, this is your dream, and you are going to do it anyway... Best of luck to you. Work your hardest. And NEVER let someone talk you into doing something you don't feel is safe. Because I promise you, they (the contractors/dive supes) will certainly try to and it just might kill you.