I agree with @ucbalumnus that college is so much more expensive than anything else that it may be the first time a relatively affluent parent has to deny their kid anything.
Some families have to deny their kids things they want based on money starting in preschool, others are lucky enough not to hit that moment until college time, others not until grad school.
It does not mean the kid is selfish either. A kid may be super considerate in all regards and just not understand about how hard it is to pay for college, unless the parents explain it. It is all about communication and honesty about the family financial situation. And this discussion should be held EARLY, preferably before your child starts researching, visiting, and dreaming about colleges. It is harder to say, “No you can’t have this thing you really want,” than it is to say, “Here are the constraints on what you can choose. Now go out and pick one of the hundreds of colleges out there that are available within these few constraints.”
I agree with @maya54 that, for some families (including ours), college education is THE number one financial priority and what you start saving for your kids from the moment you get married. Even so, college is a huge expense beyond any other. I think it is important to let your child know as soon as you know what you will be able to afford and not afford. Then, when the time comes, help them see how very many colleges will work within that budget, so they can start researching and getting excited about those that do. And, always, communicate your love for your child and the belief that they will have a great college experience and a successful life because of who THEY are, not because of the name of their college. (This should be communicated anyway, even if your kid is going to Harvard!)