All 11 tournaments this year have been won by players 23 and younger.
Shin began the final round two shots behind overnight leader Gerina Piller, but charged past the American and into the lead with three birdies in the first five holes.
She added another birdie with an eight-foot putt at the 10th and closed with eight consecutive pars to end her victory drought after a bunch of near-misses that included 20 career top-10s.
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Playing in the penultimate group, Shin posted a bogey-free 67 for a 14-under 270 total.
South Koreans Amy Yang (71) and Hur Mi-jung (71) tied for second with Piller (73). Hur nearly aced the par-three 17th.
"Right now I have nothing on my mind, absolutely nothing,” Shin, who was bogey-free over the final 43 holes at Las Colinas Country Club, told Golf Channel.
"I think it will hit me when everything is over and I get on a plane and get home to my mum." Piller, winless in 124 LPGA starts, struggled in the gusty conditions in her hometown event, much to the disappointment of a supportive gallery.
She did not miss a green in regulation in the second and third rounds, but it was a different story on Sunday as she accrued five bogeys, along with three birdies.
(Reporting by Tim Wharnsby in Toronto; Editing by Andrew Both)
