Less than three years out of university she was into her first management role, and her career path has been a steady upward progression of management and senior analyst roles in fields ranging from telecommunications to forestry, accountancy and property.
Most recently she spent three years as operations manager with Crockers Property Group and she seized the opportunity to move right on to the coalface of property transaction by taking the helm of the REINZ.
She arrives when the worst shocks are probably over but many firms are working as never before to survive.
"It's been pretty much adapt or die for the industry. Survival depends on it," she says frankly.
"Turnover nationally is 60 per cent of what it was five years ago and most companies are lucky if they are making 15 per cent."
Nationally there were 120,000 house sales in 2004; the figure was down to 62,000 for the year to December 31, 2011, she said. Graham Lester, director of Maggie Dixon RE of Whangarei and spokesperson for REINZ Northland, also at the interview, put it into local perspective with some figures for Whangarei - house sales to December 31 last year were just 611, compared to 1540 in 2007.
Apart from the legislative changes, and today's focus on getting the best price for the vendor, client expectations had also changed radically, said Ms O'Sullivan.
"People are arriving at the door of the RE companies a lot better informed than they used to be. These are people who live in digital space, they have done their homework and tend to be very astute, very clued up about what is on the market. They will have attended a lot of open homes. Serious buyers come to open homes expecting to be able to look at LIM reports and titles and get information on anything from schools and the neighbourhood to medical facilities centres and public transport.
"They make notes and they have spreadsheets. They are likely to prefer to meet a salesperson at a property they have identified rather than driving round with him or her, viewing properties the salesperson believes meet client needs - which makes it much harder to get to know a client because the amount of personal contact is much more limited than it used to be."
Despite all the changes, selling houses is still very much a people business, involving commitment to "thinking and listening" to clients to get a true understanding of their needs, she says.
Real estate was often a second or third career for those in the industry, who brought valuable life experience and people skills to the job.
Ms O'Sullivan takes the reins at a time when the freewheeling, over-populated industry of the boom years is gone forever and while changes are still being worked through, she says "it's all good".
"The changes are definitely for the better. Ultimately it is all about consumer protection."