That's true. In the US, you can not take law and become a lawyer as an undergraduate. It's a grad only program. You must first get a bachelor's degree - any major is fine, actually. Do very, very well there, take the LSAT exam, and then apply to law schools.
If you can find an undergrad school with a pre-law program, that can help. Pre-law is not a major. It's a system of advisement. So you can be, for example, and English major who is pre-law. But you don't *have* to have been pre-law in order to apply to law school.