In the book "Diver Down" there is a chapter with phrase. "Beware of the inexperienced Expert", So true.
When I first started diving and had 20 or so dives the Advanced cert. I thought of myself as a Diver. When I logged my 100th dive, I really thought that I was hot stuff. About a thousand dives after that. In dawned on me that I was such and idiot back then. 500 dives after that there is still so much more to learn.
My advice to new divers these days is. Take some classes, get as much bottom time as you can and like the book says "Beware of the Inexperienced Expert". Find a buddy or an instructor who has learned from their mistakes.