Dreams are great. When you graduate high school–when you graduate preschool!–everyone wants to know, “What do you want to be when you grow up?”
Tell them something, for sure. “I want to get a Ph.D in political science and run for congress.” “I want to perform on Broadway.” “I want to solve global warming.” “I want to cure cancer.”
You should pursue that dream as best you can, but you should also understand that dreams are fluid things, meant for guidance more than achievement.
You will have encounters along the way: successes, failures, barriers that change your trajectory. Allow your dream to be fluid enough to change with your trajectory.
Don’t not have a dream. Don’t have such a flimsy dream that you can’t chase it. (“I want to get an A on all my freshman midterms” isn’t much of a dream!) Don’t have a dream that changes every day with your whims.
Dream big, but understand you’re aiming not for a mountain but for a slow-moving cloud.