The former music teacher from Brisbane is in Sweden with her husband Noah before the Song Contest begins on Friday.
"We are taking a lot of risks in this performance," she told SBS News.
"If it works it's going to be amazing. If anything goes wrong it can be a disaster."
Im said the scale of the Eurovision juggernaut, with its 200 million-strong global audience, was starting to hit home.
"I feel terrified that I'm doing this huge thing and so many eyes are going to be on me," she said.
"On the other hand I'm like 'this is amazing, I'm so lucky to be here'. I'm fighting between the two emotions and I hope to focus on the enjoyment more rather than being terrified all the time."
Im said she had long been a Eurovision fan.
"When I came to Australia as someone from South Korea who just moved, who didn't speak much English and felt like I couldn't completely fit in with the other kids, watching Eurovision was like a breath of fresh air," she said.
"People get this break through Eurovision from all the other heavier things that are going on in all of our lives."
Bookmakers currently have Australia ranked fifth out of the 42 nations competing in this year's context and there are whispers Im may have what it takes to be the first Australian to win the competition.
"I don't know who's going to win, but I did picture, 'what if I do win and I don't know what to say?'" she said.
"I might have to prepare something just in case. If it doesn't happen I'll just hide it in my pocket."
The 2016 Eurovision Song Contest will be broadcast on SBS’s Eurovision Weekend - Friday 13, Saturday 14 and Grand Final Sunday 15 May, 7.30pm on SBS, with LIVE early morning broadcasts from 5am on Wednesday 11, Friday 13 and Sunday 15 May.
