Jazz Carlin insists her previous Olympic heartbreak is preventing her from getting carried away about the prospect of a medal in Rio.
The 25-year-old considered quitting after illness meant she missed out on Team GB selection for London 2012.
Carlin, who represents Wales, is being tipped for a possible podium spot at the Rio Olympics this summer.
"I won't take anything for granted; I don't want to say I'm on the team," she said.
"There are a lot of people fighting for those spots. So that's the first aim for me.
"Obviously I have to get there first. Four years ago I didn't get onto the Olympic team and it was tough, I was gutted."
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Since her Olympic heartache, Carlin won 800m freestyle gold and silver in the 400m freestyle at the 2014 Commonwealth Games.
She secured two gold medals at the European Short Course Championships in 2004 and won bronze in the on 800m freestyle at the at the 2015 World Aquatics Championships in Russia.
The Olympic trials will be held in Glasgow in April but Carlin is remaining calm about her prospects.
"My coach (Dave McNulty) is already talking about Rio and he's got every confidence in me. But I'm keeping my feet on the ground," Carlin told BBC Wales' Sport Wales programme.
"It's hard (to win a medal). I'm trying to make up for a lot of heartbreak and don't want to think about it.
"First I have to get on the team. I have dreams, but I need to do everything to get on the team and then the podium.
"It's all about Rio 2016, it's all about Olympic year and you want to be at your best in 2016."
After nearly giving up the sport, Carlin reflected: "I considered quitting, I was really close.
"The sport is tough, a lot of hours and when you aren't achieving your dreams it can be really hard.
"But I am lucky I gave it this one last shot."