He became principal at a school at which he had already worked for 12 years.
Nevertheless, like many of his peers, the new principal said more work could be done to set up incoming heads for success.
After taking on the role this year at Green Island School, Mr Warrington said becoming principal at a new school would have been totally overwhelming.
His view is backed by research released by the Education Review Office (ERO), saying only a-quarter of new principals felt prepared when they started.
Despite having more advantages than most, Mr Warrington said he felt underprepared when he first started and an induction process would have been very helpful.
ERO education evaluation centre head Ruth Shinoda said more than one in three principals had under five years’ experience in the role.
"We heard that the complexity of the role and the reality of the school they are in are two key reasons new principals arrive feeling unprepared or anxious."
The ERO report said new principals who had the opportunity to hold a leadership role before becoming principals were twice as likely to be prepared when they started.
Mr Warrington had been the assistant principal and a member of the board of trustees at Green Island School before he became principal.
He said building relationships with staff and a new community would have been very difficult while learning all the duties of a principal at a new school.
"It would take you at least a year to work out how the school works and understand the division and strategic direction.
"If you’re coming into a school that’s already got a strategic plan, having to get your head around that and how it’s working, you’d be really reliant on the management that is already there."
Mr Warrington completed a bachelor of commerce degree in marketing and finance during his time at university and said it made a huge difference to know basic accounting.
"If I take that away and I didn’t know the staff, oh my goodness, I can see why people quit really fast.
"Hence, that’s why I think that maybe the way forward, is being at the school and being internally promoted — it is probably more successful in keeping people."
Secondary Principals’ Council chairwoman Kate Gainsford said the education system needed to make sure principals were well prepared for school leadership roles.
"There needs to be clear leadership and direction to achieve the best combination of professional support and development for aspiring leaders."
