There's a lot to learn for the Private. The reason I recommend getting the ground school stuff done or at least a good chunk of it done first is if you start flying first you'll have no idea what's going on and get overwhelmed faster. For instance on your first several flights your instructor will probably be telling you "more right rudder." It would be really helpful if you know why you need more right rudder and where to look to tell what rudder inputs are needed. 3 times a week is probably ideal when you first start out. It takes time to process what happened when you're first learning. Once you feel comfortable flying the plane, picking up the pace on training is fine.
Yes, there are "rules of the road." You'll find those in the private pilot training books and AIM. If you're eager to get started with books, I suggest "Airplane Flying Handbook" "Pilot's Handbook of Aeronautical Knowledge" "FAR/AIM" Sportys.com sells the Airplane Flying Handbook and Pilot's Handbook of Aeronautical Knowledge for $26 for both and FAR/AIM for $12. I'm pretty sure you can download the first two books in PDF form from the FAA for free.