The sad truth is that opportunity doesn't knock twice. You can put things off until tomorrow but tomorrow may never come. Where will you be a few years down the line? Will it be everything you dreamed of? We seal our fate with the choices we take, but don't give a second thought to the chances we take.
You decide you'll wait for your pitch. Then as the ball starts toward the plate, you think about your stance. And then you think about your swing. And then you realize that the ball that went past you for a strike was your pitch.
Opportunity knocks at every man's door once. On some men's door it hammers till it breaks down the door and then it goes in and wakes him up if he's asleep, and ever afterward it works for him as a night watchman.