IMHO you start in the lowest class offered to get your feet wet and learn how to turn laps SMOOTHLY before you strap on a fully adjustable suspensioned rocket sled. The learning curve is straight up if you don't spend any windshield time in a fendered car. Learn what it takes to drive in traffic, work your way up to the front, and lose/win graciously.
I absolutely GUARANTEE you would get frustrated and quit before you even got started if you tried to race a mod right outa the box.
You didn't just strap on a chute and jump out of a perfectly good airplane with out LOTS of training and preparation first.
I compare circle track racing to actual combat, and I train and prepare car and self accordingly.