Democratic systems are generally of two types: direct democracies in which every person participates and votes; and representative or indirect democracies, in which every person participates in selecting representatives that vote for them.
Autocratic systems are generally of two types: single person or elite group dictatorships.
The USA is an autocracy in which the elite manipulate an array of interacting systems and manage the people.
The USA began as a colony of the British Empire. It has always been an oligarchy. It has never been a democracy: or even a democratic republic.