She shared the clubhouse lead after half the field had completed the first round.
"My friend put champagne on me," the 31-year-old South Korean said, explaining her wet clothes.
"I'm very happy to be back on tour. I was nervous on the first tee."
Choi did some soul-searching during her long injury-enforced absence with what she described as a disc problem.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Her body was ailing, but so too was her mind after years of single-minded focus on little else but golf.
She had developed a reputation for being unduly harsh on her caddies, though most likeable off the course.
"I think I was kind of robot, when I was growing up and then playing golf well on LPGA Tour. I think I was like living in the box.
"I couldn't do anything beside golf, only golf, only golf; like 100 percent focused on golf. I think that's why I got a little bit burned out."
Choi spent a couple of weeks travelling in Europe, where she temporarily shed her regimented lifestyle and lived like a typical tourist.
"Everything was kind of new experience for me and I really enjoyed it," she said.
"I didn't think about golf. I didn't set alarm every day. I just woke up whenever I wanted and I just eat whatever I wanted."
After several months she felt the desire to resume golf return and with rehabilitation her back improved enough for her to start playing again.
But rather than grinding on the range, Choi just tried to enjoy herself with friends.
"I try to drink some beer and get a little tipsy playing golf because we always play golf in serious mode," she said.
"I just like to play more fun and that's how I did today."
(Reporting by Andrew Both in Cary, North Carolina, editing by Ed Osmond)
