VANCOUVER, Canada, Aug 26, 2012 (AFP) - South Korean-born Ko finished the 72 holes on 13-under-par 275 at the Vancouver Golf Club course to beat Park Inbee by three shots. 
"I just came to make the cut and play the best," said Ko, 15. "I won and I'm going to get the trophy, and it's amazing."
The fifth amateur winner, Ko is also the first since JoAnne Carner captured the Burdine's Invitational in 1969.
Ko is 16 months younger than Lexi Thompson, who held the previous age record at 16 years, eight months. Thompson set the mark when she won the Navistar Classic last year.
Ko was born 11 days after Tiger Woods won his first Masters in 1997.
She finished five strokes ahead of South Koreans Choi Na-yeon, Shin Ji-yai and Chella Choi, who finished in a tie for third place at eight-under 280.
Earlier this year, Ko won the New South Wales Open in Australia at 14 to become the youngest player to win a professional tour event. Ko also won the US Women's Amateur two weeks ago in Ohio.
Ko pulled away with birdies on five of the first six holes on the back nine.
Because she is still an amateur, Ko does not get to collect the $300,000 in first-place prize money.
Asked what she would do with the money if she could keep it, Ko said she would buy a dog.
"I have always wanted a dog, but we don't have anyone to care for it," Ko said. "So maybe I would use it to get a dog."
She said she would also donate half of any windfall to "people who are in need of money."
Ko began the tournament with two straight 68s and shot a 72 on Saturday, giving her a one-shot lead heading into Sunday's final round.
She showed the maturity of a seasoned champion on Sunday, routing the field with her best round of the tournament.
Ko moved with her family to the Auckland area when she was six years old. Her gallery included a contingent of South Korean expatriates and Kiwi fans -- some of whom were carrying the flag of New Zealand's beloved All Blacks rugby team.
Playing in the final group with American Stacy Lewis and Shin, Ko got off to a strong start by making birdie on the second and sixth holes.
On the back nine, Ko took off. She helped seal the victory by making birdie on four straight holes, beginning on the 10th. She got to 14-under with another birdie on the 15th.
Ko made bogey on the par-four final hole but it didn't matter, because she had a sizeable enough lead by the time she reached the tee on 18.
There are no immediate plans for Ko to turn professional. She wants to finish high school, then play college golf first.
"I've come to realize it doesn't matter," she said. "When I turn pro, I'll get the money, so... hopefully I'll get many wins."
Leading scores on Sunday after the fourth round of the LPGA Tour's Canadian Women's Open (USA unless noted, x-denotes amateur, par 72):
275 - x-Lydia Ko (NZL) 68-68-72-67
278 - Inbee Park (KOR) 68-71-70-69
280 - Na Yeon Choi (KOR) 67-72-73-68, Chella Choi (KOR) 72-64-73-71, Jiyai Shin (KOR) 70-70-69-71
281 - Stacy Lewis 72-71-66-72, Anna Nordqvist (SWE) 74-70-68-69
282 - Haeji Kang (KOR) 72-71-72-67
283 - Vicky Hurst 70-70-72-71, Jane Rah 71-71-72
284 - Moira Dunn 69-70-72-73, Catriona Matthew (SCO) 74-72-67-71, Azahara Munoz (ESP) 73-71-71-69, Gerina Piller 73-74-70-67
285 - Taylor Coutu 71-70-71-73, Mina Harigae 73-70-69-73, Jessica Korda 72-71-71-71, Sydnee Michaels 70-72-69-74, Mika Miyazato (JPN) 71-71-73-70, Suzann Pettersen (NOR) 71-69-73-72, Dewi Claire Schreefel (NED) 72-71-72-70
286 - Ilhee Lee (KOR) 73-73-72-68, Paige Mackenzie 70-76-71-69, Mo Martin 74-71-73-68, Stacy Prammanasudh 72-73-72-69