The conversation isn't going anywhere. The classes thing isn't something you care about. Nor does she care about talking about it. You need to have a more man to woman vibe and try to flirt.

Bro first stop apologising for slow response it decreases your value and your convo topic is boring and platonic ask her questions like "whats your passion" , tell me the basics question, what types of guys she is into and make sexual innuedos like if u are talking about your hobbies add a line of kinky activities, then if the convo is bit sexual go with "whats your fantasies" and finally soft and hard close her for a date