She's a young, attractive, bright, inexperienced and (I would argue) naive politician who rode a small-scale populist wave and a weak opponent and got lucky timing-wise. I'm reasonably confident her popularity outside her district has surprised even her, even though she's got a pretty leverage-able platform from a large media market. She scares the other side of the aisle (Republicans, and moderate Democrats, a bit) because their wings can't offer up anyone to counteract her vivacity and enthusiasm on a local or national stage. When she effectively (not explicitly) got behind Biden after Sanders withdrew, a few of the crank pundits who were all-in with Sanders turned on her. Didn't hurt her a bit. She's inside the system though, unlike Sanders -- a Democrat, not an Independent. A "change from within" type. Very savvy in that regard.