Be Born Yesterday Meaning

Example :   I was not born yesterday, you know. I have done this before!1915, William MacLeod Raine, Steve Yeager, ch. 6:  "Say, do I look like I was born yesterday? See any green in my eye, Cactus Center?"1998, Gwyn Hyman Rubio, Icy Sparks‎, page 155:  "Compared to me, you were born yesterday."2005, Howard Zinn and Donaldo Pereira Macedo, Howard Zinn on Democratic Education‎, page 69:  If you don't know important things about history, then it's as if you were born yesterday.