It seems her last job was in a restaurant, though I don't know in what capacity; however, that's somewhat irrelevant for
some 50 or so members of Congress opt to make their office their home. Such members need not bother with much other than outfitting their office with something that passes as a bed.
I suppose that's not surprising as rents within walking distance of the US Capitol and the House and Senate office buildings are quite pricey. If, on the other hand, they are willing to commute to work, perhaps via the subway, or as Joe Biden often did, by Amtrak, there are plenty of reasonable places they can dwell.
In any case, Ms. Ocasio-Cortez is, in a manner of speaking, discovering what was self-evident to many members of Congress from 1789 to the 1850s or so: to be a member of Congress is to serve the country and as such, one is well advised to do so for a time and get the hell back to one's home state/district and resume one's professional life. Of course, in those days, the only people who could get elected were also business owners, which, as any careful study of US history knows, is for whom the US was created; thus it's no surprise that's the social cohort from which our earliest legislators were drawn.
It's astounding to me even now that prime-earning-age folks come to Washington from decent-to-lucrative jobs ($300K+/year) to take a modest salary -- $175K, which in DC and having to use it to support a family back home, ain't much at all -- and then incessantly, until one is voted out, enters one's dotage, or dies, run for reelection...I damn sure wouldn't do it unless I hailed from a place within daily-commuting range.