There is a line from the poem "If... " by Rudyard Kipling which seems to answer well the question of when one is ready for competition:
Quote
If you can meet with Triumph and Disaster
And treat those two impostors just the same;
Evidently this line is written on the wall of the players' entrance at Wimbledon, reminding competitors of the importance of good sportsmanship and winning/losing with grace.