Your best bet is to start out prepping a car and pitting and learning the back side of the racing program. The more you know on the mechanical side of racing will Start you off in the right direction.
My advice would be to go to a few races with different promoters and see what type of racing you want to get into. BITD and SCORE are the more expensive desert series to get into and are going to require more pit support compared to a smaller series such as the Pure series in California City , Ca. You can also get away with a far less extensive and expesive build in the smaller series.
KEEP IF FUN whatever you decide to do !
Like they said, set out to have fun. I started in the PURE series last year and decided to go race with the big boys. The small series stuff is fun and much cheaper. The car is much less complicated in the fact the cage can bolt on, you don't have trackers and and for me it was closer to home. I had a great time but there were things I did not like that my friends in the BITD said was not an issue. But even the entry fee is what more money. A Pure race in the pro class is like 380 the Mint is 1200 bucks just for entry fee.
Practice makes perfect. You will see at these races, lots of people just go out on lap one and destroy their stuff. The first lap of a Pure race looks like a UTV junk yard. Every race seems to have some guy driving way over his head and upside down in the ditch.
Dirtfish is a great school, but it will not teach you what just good old seat time will. Liek was said you need to learn how to prep the car. Lots of guys can't even make their car last the first 20 miles. No sense paying 1200 bucks to only race 20 miles cuz you don't know basic mechanics.