Yes all achieve-able. Im a 23 year wildland firefighter who worked my way up the ranks on a Hotshot crew and now a District Fire Management Officer. I stuttered all the way to the top and continue to everyday. Some days are better then others. I realized that I am very good at what others are not. There are qualities of life that are influenced by fluency but if you can figure what some of the others are that will enhance your ability to reach your goals it is possible. That is what worked for me.