inexperienced driver combined with a new car and there's far too many variables here to determine exactly why the car is in consistent in 60 feet.
I'd suggest having an experienced racer watch you from the moment you roll into the water through staging and launch.
I also suggest setting the tires at a psi known to work and not touching them for the rest of the day.
Others things...
length/time of burnout needs to be the same every pass, stage at exactly the same temp every pass, launch at exactly the same RPM every pass, get more seat time.
Again, way to much tire!