Cool and congrats on finishing your first race.
Tire pressure is a much debated topic in CX. I am around 165lbs and ran my last race at 26psi front, 28psi rear on 33mm tubeless tires. On my other bike with tubulars, I would be more like 22-23psi.
Typically you want the tires as soft as they can be without bottoming out and striking the rim on the ground. For most people, it's lower than they are used to, so practicing riding around in a park at lower PSI can be helpful to get used to the feeling.