Welcome! Assuming your car is “stock” (more or less as it would have come off the showroom floor), then it is in GS. Automatics can be fun, I nearly won open HS in an auto Civic a few years ago.
We accept any helmets with at least a DOT rating but it has to be full face or open, no “skull caps”.
You can run in open GS or Novice GS (NGS). If you have further classing questions feel free to ask me.