About 14,000 children have sat the first paper in the new transfer test in Northern Ireland on Saturday.
The common transfer test is run by a body called the Schools Entrance Assessment Group (SEAG).
The tests are the biggest change to the post-primary transfer system since 2008 when the state run 11-plus test ended after about 60 years.
The common test replaces separate tests run by AQE and PPTC, held for the last time in November and December 2022.
Ahead of the first test, pupils at St Paul's Primary School in west Belfast told BBC Radio Ulster's Evening Extra programme about how they were feeling.
Matthew, 10, said: "It's just one test, it's not going to determine your life, you've got your A-levels, your GCSEs. In a job interview nobody is going to ask what you got in your transfer test when you're 10 or 11."
Lacey, also 10, said it was important to remember all the preparation pupils have undertaken.
"Just believe in yourself, don't get yourself worried about everything, just believe in yourself," she said.
'Work hard and do well'
The school principal, Sean McNamee, moved to reassure parents who were feeling anxious about the process.
"The biggest influence over any child is the support they get at home.
"So what I would say to any parent who might be worried, as one of the children said: 'The sun will still come up tomorrow, regardless of what the outcome is'.
"But what will have a huge impact on your child's success in their future is if you continue to support them in the way that you have done in recent years.
"If you're determined and work hard, you will do well."
There are to be two tests this year - on Saturday 11 November 2023 and Saturday 25 November 2023.
Tests are controversial
Both new test papers will have questions on English and maths, and there will also be an option for pupils to be assessed on Irish rather than English.
English or Irish will be examined through punctuation, spelling and grammar using multiple choice questions and there will also be a written comprehension test.
The maths part of the test will also be mainly multiple choice questions.
Pupils have an hour to sit each test paper.
The results will be sent to pupils at the end of January 2024 and used by 62 schools - the vast majority of them grammars - across Northern Ireland to decide which pupils to admit.
The chairperson of SEAG, and principal of Regent House School, Michael Carville, said he was "delighted" that "after several years of detailed planning" the tests were now going ahead.
"Pupils will be warmly welcomed into schools which have worked very hard to ensure everything runs smoothly for the children," he said.
"Everyone involved with SEAG congratulates the children on their hard work preparing for the assessments and wishes them all the very best over the next few weeks and beyond."
The transfer test has proved controversial, however, with a number of criticisms of academic selection and calls for change.
For instance, a paper from Queen's University Belfast published in 2022 claimed that academic selection perpetuated division in wider society in Northern Ireland and "disadvantages the already most disadvantaged".