I went to dance class.......I was six.

[abo.omar]

I think the answer is until which means I finished learning when I was six. Is it correct?
is the phrase dance class correct or should we use a or the before it ,
or even use dance classes?

 

[emsr2d2]

The singular "dance class" can be used as a collective term to mean "dance school".
The only word that leads to a grammatical sentence is "until".

 

[Tarheel]

Because you stopped going to dance class doesn't mean you stopped learning.