In the USA, a bachelor’s degree takes four years. The first year is often an exploratory year in which students can discover themselves and their interests. After this year, it will be easier to make a good study choice.
So you do not have to register at a university for a specific study, as in the Netherlands. It is of course useful to have an idea of the direction you want to go in, so that Slamstox can make a selection of universities that offer the best studies in that field.