"My classmates may be surprised to see me back at school, but I'm confident that I will set sail one day. I know I can do it," she told the Jeugdjournaal programme.
Mr Dekker had earlier had a request for her to miss two years of school turned down.
Miss Dekker had planned to spend about two years aboard her 26ft (8m) boat, Guppy, to break the record set this week by a 17-year-old UK boy.
Mike Perham tackled 50ft waves, gale force winds and technical problems during the 28,000 mile (45,000km) circumnavigation, which took him nine months.
Addressing concerns that she would be alone for long periods on her round-the-world trip, she told Jeugdjournaal: "I will always be surrounded by other people who are on a journey like mine. I really think I will meet these people and make friends easily."
The Dutch Child Protection Agency had requested Miss Dekker be made a ward of court because, it said, it was "irresponsible for such a young girl to make a two-year solo trip around the world".
Child Protection spokesman Richard Bakker on his concerns
The judges agreed, ruling Miss Dekker would face mental and physical risks if she were allowed to go ahead with her planned record attempt.
Miss Dekker was put under the guardianship of the Utrecht Youth Care agency and the case will be reviewed after two months.
Peter de Lange, the Dekkers' lawyer, described the case as "exceptional".
"The crucial question is whether it is wrong for parents to allow their child to indulge in her passion," he told Radio Netherlands.
Caroline Vink, a senior adviser on youth protection in the Netherlands, said the case needed to be "looked into".
"We're talking about a 13-year-old," she told the BBC. "You can also question whether she's able to take this decision for herself, and whether the parents are making the decision in the best interests of Laura."
Miss Dekker was reportedly born on a yacht off the coast of New Zealand during a seven-year world trip.
She had a yacht by the age of six and began sailing solo when she was 10.
"Since I was 10 years old, I've known that I would like to sail around the world," she had earlier told Dutch television.
"I want simply to learn about the world and to live freely."
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