The First Minister said Scottish education is not good enough, with a decline in reading and writing skills and too many deprived children held back unfairly and denied the opportunity to go to university.
She said it is her “sacred responsibility” to make sure every child succeeds in life, and has pledged to make education the driving and defining priority of her government.
Writing in the Daily Record, she said: “Now that I am First Minister, I am determined - indeed I have a sacred responsibility - to make sure every young person in our land gets the same chance I had to succeed at whatever they want to do in life.
“The hard fact is that too many young people are still held back, unfairly and through no fault of their own, by the circumstances into which they are born.
“Tackling this will take us well beyond education. But education is vital.”
She added: “So how are we doing as a country when it comes to education?
“In seeking to answer that question openly and honestly - as we must do if we are to make real improvements - I disagree with extreme opinions at both ends of the spectrum. Those who say Scottish education is failing badly are wrong.
“But let me be clear - those who say it is good enough are wrong, too.”
Fewer children are leaving school with no qualifications and more are leaving with several Highers, including from deprived areas, she said.
“These figures are still not good enough,” Ms Sturgeon added.
“Similarly, while more youngsters from our least well-off communities are now going to university, the numbers are still far too low.
“Recent evidence suggests standards of literacy and numeracy in our schools are falling. That is unacceptable.”
The Scottish Government is expanding childcare, maintaining teacher numbers, established a £100 million fund to improve literacy and numeracy in deprived areas, appointing attainment advisers in every council, investing in new college buildings and keeping university tuition fee-free, she said.
“Over the next months and years, making sure the Scottish education system becomes, genuinely, one of the best in the world will be a driving and defining priority of my Government,” the First Minister said.
“We will not shy away from making changes - and tough decisions - if they are in the best interests of our young people.”