Most importantly:have fun!
I started gravel from road this year. The only "mistake" I had was not having the bike fit right when I took my road bike fit numbers and moved them to the gravel/cross bike. The geometry is totally different so did a couple of rides that killed my quads before I sorted it out.
People perseverate over tire width. Probably whatever comes stock is a good place to start.
Where I am gravel roads are definitely less traveled, so I try to make sure that I have most things I would need to get me closer to civilization if needed due to mechanical. Extra Link, extra battery, bacon strips, multi tool, pump, etc.. Also sunscreen and bug repellent before forest rides in the summer.
Welcome to the club!