Belgium have been drawn alongside Russia, South Korea and Algeria in Group H at the upcoming tournament in Brazil.
With coach Marc Wilmots able to call upon the likes of captain Vincent Kompany, Eden Hazard and Romelu Lukaku, many see Belgium as dark horses at the showpiece event.
But Mignolet, who is set to be understudy to Thibaut Courtois, told FIFA.com he remains cautious about his country's chances.
"The first objective was to qualify," said the 26-year-old, who has earned 15 international caps since making his debut against Austria in 2011.
"It's been a long time since that happened and we're delighted to be making the trip to Brazil.
"Our next goal is to make the second round. After that, we'll just have to wait and see."
Mignolet, who narrowly missed out on the Premier League title with Liverpool this season, added: "On a personal note, it's a childhood dream come true to be taking part in an event like this."
Belgium continue preparations for the World Cup with friendlies against Sweden and Tunisia before facing Algeria in their opening group game on June 17.
