according to that graph she's right there with multiple credible Presidential candidates and as you mentioned she's a freshman rep. I mean Obama went from state senator to president in 4 years.
credible was the wrong word to use. buttigieg ran a credible campaign. people took him seriously and he impacted the direction and outcome of the results. but he never had a chance of winning. maybe competitive would be a better word. aoc could run. she'd raise a ton of money. she'd get press coverage, she'd probably impact the race in some way. but she wouldn't win.
re. obama, it was probably important that he won a statewide race before running. i don't think he'd have won without that legitimacy. but even at that, i don't think 2008 obama could have won in 2020. experience and an established political identity were more important this last cycle than in 2008. the electorate was in no mood for hope and change in 2020. we'll see what the electorate wants in 2024, but i'm guessing it will be closer to 2020 than 2008.
farther out than that, god knows, but, one way or another, aoc won't be a fresh face by then anyways.