The "just a bartender" narrative was fake. All throughout AOC's college career she was clearly following the CIA/USAID "let's groom photogenic young minorities for political careers" pathway, complete with international scholarships and interning for Ted Kennedy. And then, suddenly, she was out on her ass working as a bartender and waitress.
I think AOC's handlers told her to slum it for a while so that she could establish a plausible "everyman" persona and narrative, and so that the grooming pathway would look less obvious. Then they concocted a story about her brother secretly nominating her in a competition (the "casting call" @XYZpdq Jr. was referring to) which randomly and fortuitously launched her political career.
It's important to recognize all this, because it explains the way she acts now. AOC knows that the establishment is responsible for her success, and that they can take it away if she steps too far out of line, and this is why there are always lines she absolutely will not cross. She's the old establishment with a new "sassy young Latina" coat of paint.