Northern Ireland is the only country in Europe to send children to school at the age of four.
However the Education Minister, John O'Dowd, has agreed to consider giving the parents of younger children born in May or June the option of deferring their entry for a year.
A Professor of Education at Queen's University believes it's important to make the system more flexible, explaining that there is no need for it to be as rigid as it is.
"There is no evidence that sending children to formal education that early confers any academic advantage, in fact if anything there's a sense there may be a slight academic or psychological disadvantage to starting so young," Tony Gallagher told UTV.
"It appears to be part of a long-standing tradition that people aren't questioning."
Children in NI who turn four before 2 July are legally obliged to start the next September.
That means if a child reaches their fourth birthday in May, June or even the first of July, they are taught with children who may have celebrated their fifth birthday almost a year earlier.
Basically, they are going to play catch-up for the rest of their school years.
Siobhan McQuaid, who is vice principal at Holy Family Primary School in north Belfast, believes the system is unfair.
"I have been teaching at Holy Family for the last 23 years and I have noticed one or two children every year are not developmentally ready for primary school," she said.
"I think they are seriously disadvantaged because there are many children in the class who are one year older than them - who are ready to colour, to hold pencils, to read, to write - and really we find these children are always playing catch-up.
"We really feel if they was a little bit of flexibility in the system and these children were allowed to take another year in the preschool setting, they would have the chance to maximise their opportunities in school."
Maureen Johnston's oldest child Andrew was born on 17 June.
He was just four years and two months when he started school in September. Given the choice she would have deferred Andrew's entry for a year.
"He was very young, he was very immature," she explained. "He's the oldest in our family so he's still quite babyish but he's paving the way for everyone else. Andrew was exhausted, he had naps after school and he was very withdrawn and lacked confidence and maturity.
"I felt frustrated, out of control. There is no real reason for it so it was such an anguished time for us, it really was."
The pressure group Parents Outloud met the Education Minister last Monday.
It has lobbied for years to introduce a more flexible system similar to Scotland's - where deferral is allowed - and the minister has agreed to consider it.
It could mean around 3,000 pupils delay their entry into P1.
The group hope John O'Dowd will announce a decision in the coming weeks so that parents of children born in May or June can choose to defer entry to P1 by September 2014.
Ms Johnston said the benefits of change outweigh the costs.
"The policy at the moment doesn't allow for parents decisions, if you're forced into sending your child to school but you don't feel they're ready," she said.
"We're his parents, we know him better than anyone else so they should allow for individuality because one size does not fit all."