And she is already outlining ambitious plans for the future of the school.
Mrs Miller will replace Jan Anderson at the beginning of term two next year, and she is very excited by the new position.
"It will be a very challenging role, but also a very satisfying one.
"My experience as a beginning principal at Fiordland College, which is a relatively small, rural secondary school, has been very stimulating and rewarding for me, both personally and professionally.
"It has provided me with the perfect grounding to gain the skills necessary to take on the challenges presented by a much larger secondary school," she said.
"I would like to see Otago Girls' High School become the top school across the board, in the country."
While she was excited about the opportunity at Otago Girls', she was also sad to be leaving Fiordland College and the wider Fiordland community.
"In the three years I have been here, I feel I have become part of the community.
"I'll be sad to leave that."
Mrs Miller, a teacher with 20 years' experience, is a former deputy principal at Blue Mountain College, former head of the social sciences department at Gore High School and has also worked for the Education Review Office and the New Zealand Qualifications Authority.
Mrs Miller said the delayed start date allowed her to complete several projects at Fiordland College, and would give the board of trustees time to find a replacement.
Otago Girls' High School board of trustees chairwoman Victoria Deaker said Mrs Miller had "the experience and personal qualities required for the role", and was confident she would continue to lead the school's vision of personal excellence.
Fiordland College board of trustees chairman Dr Chris Shaw said the promotion was a tremendous opportunity for Mrs Miller, but the school was "extremely sorry" to be losing her.
"The school has thrived under her exceptional leadership over the past three years and she has been a pleasure to work with."
