When my eldest daughter was three years old, she decided to grow up to be a fire truck. No matter how many times someone tried to correct her based on their world view, she adamantly proclaimed she wanted to be a fire truck. She knew best what she wanted to become.
She no longer wants to be a fire truck but she still knows best what she wants to become. The trick is to stop listening to the crowd and start listening to your heart. And then believe.
What do you want to be when you grow up?