Her parents did not want her to be a dairy farmer and suggested she go to university. She graduated from the University of Otago with a physical education degree in 2007, before getting a job milking cows. She now managed a team of four full-time staff, a milk harvester and a calf rearer.
At the regional awards, she also won merit awards for employee engagement, livestock management, dairy management and leadership.
She believed being a good all-rounder contributed to her success. A good farm manager had to be prepared to be a jack of all trades and accept that they would not have time to be fantastic at everything, Miss McCrostie.
She first entered the dairy awards last year and did not make it to the final, but it was good experience, she said.She believed one of the benefits of entering the competition was that the process highlighted areas for improvement.
"It also forces you to consolidate all your farm data and help benchmark, reflect and justify decisions," she said.
Being judged was not a daunting process as the judges were very friendly and she encouraged others to enter the competition, Miss McCrostie said.
"I'd almost say they are not there to judge but point out things you could potentially work on. It's encouragement, " she said.
When it came to what she loved about the dairy industry, Miss McCrostie said it was a multi-disciplinary challenge.
It was being outside, working with animals, while there was also a lot of paperwork and a lot of learning and new technology involved.
"My best piece of advice to people is to back yourself. The biggest gains are made when you take the biggest risks.
"But if you do drop yourself in the deep end, make sure you have the right support team around you," she said.
She was part of the Family Works buddy programme, which provided support, fun and new experiences to children in need of a positive influence in their lives.
She and her 11-year-old buddy spent a couple of hours a week together "just hanging out".
"We just get together and go and do kids' stuff, which I reckon is just as beneficial for me as it is for him," she said, laughing.