The 19-year-old debutant was placed third in the final and attempted a backside 1620 in her last run to try and lift herself towards the top of the standings in Milan-Cortina.
She completed the four-and-a-half turns required, but over-rotated on landing and slipped out of medal contention into fourth, as Japan's Kokomo Murase took gold.
Brookes, though, said she was proud to have pushed herself to the limit despite coming away medal-less.
"Obviously I'm bummed I couldn't land that last trick," Brookes said. "It's a really special trick and, for women's snowboarding, if I'd landed that it would have been insane.
"I wasn't planning on it and I didn't want to do it at all. But I think sometimes you've got to just grit your teeth and get it done. I'm just stoked I tried it and I'm not lying in a hospital bed."
Brookes will return to action in the slopestyle next Monday – the event in which she made history as the youngest-ever world champion in 2023.