On Thursday, Rachel Lee took Theodore Roosevelt’s advice to ‘speak softly and carry a big stick” to heart. Saying little and with her mother, Jung, carrying the bagful of big sticks as her caddie, the 16-year-old Sydney schoolgirl shocked the golf world by crashing a first round six-under 67 at The Lakes in her home city to lead the 2023 Australian Open.

“It was fantastic – a dream come true,” Rachel’s father, Jay, told the Guardian. “Lots of memories came flashing back – Rachel first picking up a golf club for the first time at a holiday camp when she was 10 … taking 11 shots to get out of a bunker in her first handicap game … putting competitions at home to see who cleans the bathroom.”

Jay Lee, a hotel manager, is resigned to being on bathroom duty for the forseeable future.

His “lovely, friendly, calm” daughter defied driving rain and a star-studded field to pouch eight birdies and top the leaderboard with America’s Jenny Shin. On Friday, she teed off enjoying a one-stroke lead over the former world No. 1 and two-time major champion Jiyai Shin, with Australia’s Steph Kyriacou one shot back on four-under.

However, the round of Lee’s young life was very nearly over before she had played a shot. The year 10 student from Endeavour Sports high school came close to disqualification for missing her tee time after mixing up her start time.

“I thought I was at 8.38am, not 8.28am,” a sheepish Lee said later. “I just ran for my life.” Her coach, Steve McRae, called it “a right old balls-up” and admitted he had to hustle his young charge off the practice putting green in a hurry to make her big leagues debut.

“But typical of Rachel, she took yet another layer of pressure in her stride,” he said. “She got up there, slotted straight into game mode and shot a great round. Even when she realised she was leading, Rachel was pretty reserved. ‘Y’know what Steve? I didn’t even realise what was happening.’ I had to remind her yesterday was pretty freaky.”

Lee is an only child from Marsfield in Sydney’s north-west who loves reading and playing flute and dotes on her dog Dodo and cat Mango. The alumni of Avondale golf club at Pymble qualified for the Australian Open on Monday by winning a qualifying event at Ryde-Parramatta golf club. It followed her first professional win last week at the NSW Open Golf regional tournament at Mollymook.

Despite being the youngest player in the field and partnering her childhood coach and golfing hero, Sarah Oh (who shot a one-over 74), Lee held her nerve to win a thrilling playoff and line up with the world’s best golfers at The Lakes.

“Rachel’s game has come on leaps and bounds lately,” McRae said. “A couple of months ago she was in a bit of a slump. It wasn’t coming together and she was down. But she’s gone back to an old putter and the confidence has returned. Rachel has worked hard, got her mindset and focus razor-sharp … except, maybe, on tee-times.”

McRae, a Wollongong-based coach who mentors golfers across the US, Japan and Korea, met Lee when she was 14. “I watched her play on the NSW south coast and saw the potential straight away,” he said. “She was calm and quiet and skilful.”

She also let her big sticks do her talking.

“Rachel doesn’t like to talk. I’m sure teenage emotions are swirling but she’s pretty self-contained so, like her parents and teachers, I try to keep it simple and don’t over-coach her, just offer support and advice.”

Lee’s school principal, James Kozlowski, does likewise but admits it may not be easy after Lee announced herself to the golf world in such style.

“Rachel is respectful and driven and gifted both academically and athletically,” he said. “But she has gone from relative obscurity to international news overnight and a new challenge is coming. She’s on the radar, under more pressure and people will start whispering in her ear. We teach our students how cut-throat professional sport can be, how a career can end in a heartbeat, but that education is for life.”

So far Lee has the balance right. Her attendance and marks are good. But since she is entering the pointy end of HSC studies, she still had to ask permission to skip class this week to play in the country’s most prestigious golf tournament.

“After Rachel won Mollymook last week, we sat down with her family and talked about the growing demands and extraordinary commitment Rachel’s talent will make on her,” Kozlowski said.

She has plenty of support in the Endeavour school halls, which are filled with young stars making their way in the NRL, AFL, A-League and many other sporting fields. Three of the school’s students are in the Australian Open field this year, with Lee joined by fellow year 10 student Ann Jang (three-over 76) and Jeff Guan, winner of the 2022 PGA Junior Championship, who carded a six-under 70 to sit eighth in the men’s standings.

Jay Lee says his only advice to his daughter is “have fun and enjoy”.

It’s easier said than done as professionalism looms, sponsors swarm and the international tour calls.

“I’m more worried about my wife,” Lee said. “She knows very little about golf and got very tired carrying Rachel’s bag so wants to use a buggy in future. But Rachel loves having her there because she doesn’t offer advice. She just cheers her on.”