"It was one year ago that she went to Beijing."
This alters the meaning: It would mean that she is Beijing (notwithstanding that 去 needs an object).
if you translated "she is a one year ago going Beijing" your translation is correct;)
You are supposed to report that to Duolingo, not post it in the comments section.
Fyi, as an experiment - i actually took a bunch of chinese people to do the "test out" for this course work and they all failed. Definitely not their problem here.
I selected those with professional fluency in English btw.
Duolingo shows 家 (pronounced as Beijing by the system) in place of 北京 for me in a number of places including this phrase.
Why doesn't this mean, "She is a year go to Beijing."
What makes this, last year?