You're not usually obligated to choose a major until you're 2+ years in. By then you're probably 20 years old.
Hell, most Uni students are 18, which means they're a legal adult. Most of them have been driving cars and fucking for years before then -- why wouldn't they be able to make choices about a career?
And that decision is made when they are legally children, and they're bound to it for the rest of their lives.