Meaning of beginner's luck

begin'ner's luck'

Pronunciation: [key]
  1. the initial good fortune or success commonly supposed to come to a person who has recently taken up a new pursuit, as a sport or game: Catching a large trout the first time you go fishing is simply beginner's luck.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.