It was a momentous occasion Thursday, and it had nothing to do with her score.
Kostina, who celebrated her 24th birthday on Monday, became the first Russian to play in the U.S. Women's Open.
'To be honest, I felt very nervous,' Kostina said. 'I didn't feel very comfortable at all the first three holes, and then I was trying to limit the mistakes in my swing. I wanted to play better than this.'
Her 22-year-old sister, Anastasia, became the first Russian in the U.S. Women's Amateur two years ago, although she failed to advance to the match play portion of the tournament.
Both attended Washington State, and both now play on the Futures Tour.
How they got both places is amazing, especially considering they were born before Moscow even had a golf course.
The first 18-hole course in their country was built about 10 minutes from their home, in the Moscow suburb of Nakhabino. Although there was a program that allowed juniors to play for free, Kostina said there weren't many takers.
'I always liked to try new sports,' she said.
She started by hitting balls on the range, not realizing there was more to golf than that. But when she played her first round, from tee to green, she was hooked.
'We fell in love with it,' Anastasia Kostina said. 'We wanted to play every day. We stopped going on our summer vacations, because the summer is not very long, and we didn't want to miss a chance to play golf.'
Playing on a national team led Maria Kostina to Washington State, where she was an honorable mention on the All-Pac 10 team and an Academic All-American for two years. Anastasia followed her to Pullman, Wash., and both earned degrees in psychology.
On the Futures Tour, they get financial support from Russian friends who live in the United States, chasing their dreams. Even though it was a bad start at Pine Needles -- Maria took a 10 on the 17th by hitting two balls out-of-bounds -- she already has learned from her first trip to the Women's Open.
For one thing, she has never seen so many fans on a golf course.
'I like it when people watch me,' she said.
She is one of six players with the surname Park at Pine Needles, but Angela Park has a history that sets her apart. Although her heritage is South Korean, she was born in Brazil, and she grew up in California, where she learned to play golf.
'I have citizenship in Brazil right now,' she said. 'When people ask me, 'Are you Brazilian, Korean, American,' I think I'm three of them all mixed up together. I'm not fully Korean. I speak English very well. I'm very accustomed to your American culture. But I was also born in Brazil. I speak the language, and I have family in Brazil. So I kind of mix and match everything.'
Park, 18, contemplated college after her sophomore year of high school but decided that summer she wanted to turn pro.
She's a rookie on the LPGA Tour this year, having finished fifth at Q-school. Already she has led after the first round at two tournaments, including the LPGA Championship. Perhaps more amazing for a rookie, she has yet to miss a cut and is 13th on the money list.
'That was one of my goals coming into this year, not missing any cuts at all,' she said.
It was an itsy-bitsy spider, but it caused Morgan Pressel plenty of concern.
She saw what looked to be a small black ant on her ankle, but it turned out to be a spider. The bite caused her ankle to swell so much that the LPGA Tour's youngest major champion in history walked with a limp Wednesday and had to cut her practice round to nine holes.
Much to her relief, the swelling subsided.
'It's still a little swollen, but it's gone down a lot, and I had no pain when I was swinging,' Pressel said. 'So that's good.'
Pressel opened with a 71 on Thursday, six shots better than the score she posted in her first U.S. Women's Open six years ago when she was 13, at the time the youngest qualifier.
Cristie Kerr is starting to putt better, even though it took money out of her pocket.
Kerr was in South Korea six weeks ago when she got so frustrated with her putting that she visited a pro shop, tried four or five putters and bought the one that felt the best. She shot a 3 under the next day, then returned to the LPGA Tour and finished third at the Ginn Tribute in South Carolina.
'I went to the Ping representative and said, 'Does it look like it sets up for me? Because it feels pretty good,'' Kerr said after opening with an even-par 71. 'I'll buy every putter if I putt that well with it.'
Lorena Ochoa always gets plenty of support whenever she plays, but this week she can recognize faces in the crowd.
'My family is here watching me play, and I think it was very special for my mom to be there, too,' Ochoa said.
She said her mother, two aunts and three close friends from Mexico are at Pine Needles, and her brother, Alejandro, was due to arrive Thursday afternoon. Her mother attends about 10 tournaments a year.
Maybe it's a good omen.
Karrie Webb's mother made the trip from Australia in 1999 and was at the du Maurier Classic when Webb won her first major.