If the level of the class is too high for you, then at the end of the class you will walk out frustrated, and with a feeling that you it was a waste of money. In order to get full value please DO NOT sign up for classes higher than your level. The teacher WILL NOT slow down the class and waste time helping you if you do not have the appropriate skills to absorb the material. Better leave the class immediately and we will try to finds a class that is better suited to your abilities. Here are the MINIMUM requiremenst for the different levels of classes:

BGN (beginner) Either never danced tango or taken any classes, or very limited exposure to Argentine tango (less than 1 month) 
BGN/INT (beginner-intermediate) limited exposure to Argentine tango (1 to 3 months of classes and social dancing ) 
INT (intermediate) Have taken classes and have attended some milongas (3 to 6 months of classes and social dancing) 
INT/ADV (intermediate-advanced) Have taken classes and have attended milongas (6 month to 1 year of classes and social dancing) 
ADV (advanced) Usually at least one year of dancing or classes 
ALL All levels will benefit.