Congratulations on your first event! Pylon-racing is great fun! Thirty five years ago, it drew me into the stuff I'm still doing today.
It's really true that some folks are better at autocross than others.
One key to remember is that in many cases, it's more "the shortest distance" than "the best line".
A few years ago, I ran my Miata in an SCCA event here in NJ and a fellow in a mostly-stock '67 Plymouth Valiant walked away from almost everyone, including me....he was good!
I've autocrossed the Spridget too,....like you, I was the only Brit car at the event. Mostly Hondas, etc.
I'm better at road racing....I think I'm too hung up on taking the best line around the pylons.
My first event was actually called a "field trials" and some of the early events I ran were called "gymkhanas"....but all basically the same as an autocross.
My favorite autocross events back then were held at McGuire Air Force Base on the *huge* taxiways. This was in the late 60s. A Sprite could get to at least redline in third gear on those big layouts.
Here's me around '69 in an event at Neshaminy Mall in Pennsylvania. They didn't require helmets!
This picture was taken around 1970. The event was held in a community college parking lot in PA. Part of the course required you to stop, and back up until you hit a cone with your back bumper...and then drag race away in 1st! Not so good for Sprite axles!