Sailing speaks in a language that's foreign to most people, and, on the first half day of most entry level sailing courses, the instructor teaches you the meanings of words and phrases that you must know. If you already have a basic understanding of those words and phrases before you go to your first class, you'll understand much more of what you are being taught.
The Coast Guard Auxiliary, the US Power Squadron, the YMCA and many other organizations teach basic sailing courses that are very inexpensive, but that will introduce you to the language of sailing and to the basic principles of sailing. I suggest you take one of those courses before you enroll in the more expensive courses at a commercial school. If you already have a knowledge of the language of sailing and an understanding of the basic principles, you'll get much more benefit out of the commercial school course.