For me i didn't become an agnostic , I just realized that I've always been an agnostic before... In fact i didn't even know that I'm agnostic, I didn't believe any superstitious as a child, i didn't believe in ghosts and other supernatural being.. I think i'm just lucky that i find science to be more interesting than joining religions.. I also got open minded friends they are very open in discussions even though some of them are indeed religious.. Evolution is introduced by my uncle since i was 8 year's old, in fact some of my relatives don't have any religion.. I guess that kind of thing kinda impacted my views on the world..