Outside of competitive eventing the second year student is majoring in marketing and psychology with the aim of producing films and media.
She is also studying some equine papers.
The Long Bay resident, who started riding at nine years old, hopes her success in the Young Rider series will be a stepping-stone to competing for national teams.
"I would absolutely love to represent New Zealand in eventing, it has always been a goal. I'm aiming for the eventing young rider or youth squads."
Ms Alexander will accept her award and $500 prize money at the Equestrian Sport New Zealand's awards dinner on July 5.
Eventing incorporates three phases: dressage, show jumping and cross-country.