Im 23 and i have a flat chest?

Look at your options: Most men actually don't care, in spite of all the silly talk. I'm going to assume that otherwise your body is that of a normal woman. Doing nothing, getting a padded bra, or getting implants are all options. Don't over-value looks; focus on being the best person you can. The big-chested much-admired cheerleader from high school commonly marries a lout and is miserable for the rest of her life.