I unlike you though have caught covid-19 nearly every year since 2020 at least once a year. For me it seems like it provides protection for about a year but it doesn't last, and is individual. I kinda just expect to catch it every once in a while at this point.
Oregon had one of the lowest COVID infection rates the entire pandemic. Surely not due to anyone being particularly careful.
Apparently my grandfather helped design something with the cages, which is just weird for me.
Also there was likely cases floating around in the US before then, that was just the first confirmed case.
According to this timeline on the CDC website[1], there was reports of presumptive cases of Covid-19 in Oregon on February 28, 2020 as well. That's close enough to your timeline that I think it's more likely she just got Covid-19 (or a particularly bad case of the flu).