Walpole won the Bay of Plenty senior girls singles tournament two years in a row and was runner-up at New Zealand under-16s junior masters in 2019.
The estimated cost of attending Hamilton College was around NZ$123,000 each year, which equated to NZ$492,000 over four years.
Her scholarship would be renewed yearly so long as she met minimum academic requirements. It covered tuition, room fees and board.
Walpole, who trained about five times a week, said she withdrew her applications from the other universities once she was offered early admission to Hamilton College.
It became her top choice after connecting with the women's tennis team members and coach over a video call.
"It's going to be a big change, but the coach is super-cool and I get along with the girls really well."
She also said it was a top-class academic university in a safe location.
At this stage, she was leaning towards majoring in neuroscience and minoring in economics.
Since she was eight she has progressed under the expertise of Tauranga Lawn Tennis Club coach Luis Luna. She started playing at the age of five.
She did not see herself playing tennis professionally but said this scholarship would ensure she could reach her full potential in the sport while working towards another career.
She would have likely had to give up tennis if she stayed in New Zealand as competitive opportunities after high school diminished, she said.
"I just wouldn't get the same level of training or competition that I'll get over there.
"I want to play my whole life and see how good I can get. I want to get to be the best I can be. But if you stay in New Zealand it's not really an option.
"I am so looking forward to it. I have always found, living in Tauranga, that it's hard to find girls my age who play."
She described the process of applying to American universities as "really stressful" and involved lots of tutoring, sitting the SATs, writing a plethora of college essays and ensuring that she got top marks in NCEA.
"Now I am way more relaxed. It was a long process, and if anyone is thinking of doing it it's definitely good to start early."
Otūmoetai College principal Russell Gordon described Walpole as a "lovely person with such an incredible work ethic".
"The feeling at our school is that she absolutely deserves everything she has got."
He said she managed to get "exceptional" grades, play tennis and netball and hold down a part-time job at New World during her last year at high school.
"And I have never known her to complain."
