In 2018 the IWF restructured the weight classes, and Koha competed in the newly created 59 kg division. She followed up her bronze medal performance in 2017 with stronger performance at the 2018 World Weightlifting Championships winning another bronze medal in the snatch and total and setting junior world records in the snatch, clean & jerk, and total.
At the 2018 European Weightlifting Championships, Koha swept gold in all lifts (snatch, clean & jerk, and the total) and became European Champion in the 58 kg division.
In 2018, coming off her Junior World Championships gold medal, she defended her title as the Junior World Champion by winning gold medals in all lifts at the 2018 Junior World Weightlifting Championships.