New Jersey native Kelly Sim gets credit for turning lemons into lemonade on a hot summer day at the U.S. Girls’ Junior Championship.

Lemons, in that Sim, 16, who lives 20 minutes away in Edgewater, N.J., inadvertently signed for a wrong score in Round 2 of stroke play and was disqualified, missing out on an opportunity to compete in match play. Sim realized the scoring error Tuesday evening and called the USGA to report the mistake.

Lemonade, in that Sim, a two-time New Jersey state high school champion, volunteered to come back to The Ridgewood Country Club to caddie for a friend.

“I didn’t know it would be a short week for me here,” said Sim, still emotional about the mistake in a national championship held so close to home.

“One of the reasons I’m doing this is it’s an opportunity for me to feel better about how I ended my week here at the championship,” she added. “I just didn’t want to leave this country club like that, thinking only about what happened.”

When Sim heard that her friend Yujeong Son of the Republic of Korea – a high school student in Norman, Okla. – needed a caddie, Sim put on the caddie bib without hesitation. The two met at a junior tournament two years ago and have been friends ever since.

“Yujeong won 6 and 5 [in the Round of 32], so I already feel better,” said Sim with a big smile, before heading out Thursday afternoon for the Round of 16. “I thought it would be really fun to help her out, so I volunteered. We have good chemistry, but it’s all her.”

Sim said this is the first time she has ever caddied. Her role is to help with yardages and to push the cart that holds the bag.

“I try to help her feel less tired or less nervous and if she has any doubt around the greens, I’ll help her if I can,” added Sim, who is entering her junior year at Academy of the Holy Angels in Demarest, N.J., and has verbally committed to Northwestern University.

“It’s fun and she’s a good caddie,” added Son, 15. “I laughed all morning because, honestly, she’s just a happy person to be around.”

Son reached the Round of 16 in last year’s U.S. Girls’ Junior and with Sim on her bag, hopes to move into the quarterfinal.

But even if she doesn’t play one more round of golf at this year’s championship, Son said the week has already provided some of what she came here to experience.

“Even if I lose, all I want to do is have fun,” said Son. “That’s why I wanted Kelly to be here with me.”

Having mustered the courage to return to Ridgewood on Wednesday to discuss the disqualification with local media, then to step back onto the course on Thursday to caddie, Sim knew it was the right thing to do.

“It was pretty hard to come back here,” she admitted. “And even though caddieing is not what I wanted or expected to be doing here this week, I’ll leave with some good memories in the end.”