Go For It Meaning

(idiomatic) To put maximum effort into achieving something.

Example:   To win the competition he has to beat his personal best, and he's going for it.‎
  He really went for it.‎
  Go for it! You can win this!
To decide to do something; especially after a period of hesitation.
  His phone was off so I couldn't ask his permission, so I decided to just go for it‎
  May I use your bathroom? ― Go for it!