He’s all of 21 years old, a mere babe in the woods when it comes to men’s professional golf. But you might want to remember his name, because less than five months into his career Michael Sim already has proven he is upwardly mobile guy.

Sim, a naturalized Australian citizen who was born in Scotland before migrating Down Under with his family at the age of 5, now has his eye on America. He earned conditional status on the Nationwide Tour in the span of 72 holes at Royal Adelaide Golf Club in Melbourne two weeks ago.

Sim lost on the second playoff hole to Paul Sheehan, but earned $76,000 and his conditional status. He will have enough cash to get into events after the Tour’s first shuffle of the season following the Athens Regional Foundation Classic. His first tournament stateside will be the BMW Charity Pro-Am at The Cliffs.

“I suppose I could come over and attempt to Monday qualify, but I’ll just wait until I’m sure to get into tournaments,’’ said Sim, who earned status on the Australasian Tour in 2006 through its qualifying school.

Suffice to say Sim, the world’s No. 1 amateur in 2005, didn’t expect to get to the United States this quickly, especially since he opted not to attend PGA TOUR Qualifying School after turning pro late last year.

“I just didn’t go,’’ Sim said. “I spent a lot of time hemming and hawing. Then it was too late.’’

Sim spent his time shooting to the top of the world amateur list in 2005, earning the No. 1 ranking by winning three prestigious events, the New Zealand Stroke-Play, the Monroe Invitational and the Sunnehanna Amateur, where he followed luminaries like Ben Crenshaw and Tiger Woods into the winner’s circle.

He went back-to-back in the Monroe and Sunnehanna, the first player to score that double in successive weeks. He also won the 2004 Southern Amateur and the 2002 Western Australia Amateur. Then, in November 2005, he turned pro and focused his attention on the Australasian Tour where a much ballyhooed debut didn’t work out as Sim had planned. He missed his first four cuts.

“I honestly thought it was the end of the world,’’ Sim said, laughing. “I was devastated.’’

He righted himself by finishing eighth in the Victorian Open and followed that with a 15th. Then came his opportunity in the Jacob’s Creek Open Championship. Sim carried the lead and confidence into the final round. As he glanced at the leaderboard at the end of 54 holes Sim saw a lot of familiar names, his included. There was Nick Flanagan, Jarrod Lyle and Peter Tomasulo bunched near the top.

“That calmed me quite a bit,’’ Sim said. “Those were guys I had competed against as an amateur. I knew I wasn’t in over my head.’’

Sheehan caught Sim, who carded a final-round one-under-par 71, with a 69. But the disappointment of finishing second didn’t last long.

“Actually this has been great,’’ said Sim, who followed with a tie for 29th at the ING New Zealand PGA Championship and stands fifth on the Nationwide Tour money list with $80,013. “I had no great expectations. Now I’m looking forward to going to the States. I’ve won a few times over there the past couple of years so I think my game is suited to the U.S.’’

Sim has been pointing toward the day he tees it up professionally in America for a long time.

His father first put a club in his hands shortly after the family arrived in Australia. Sim was a casual golfer until he turned 13. That is, he said, when he became serious.

He was a scratch player by 15 and enrolled in the Australian Institute of Sport, where PGA TOUR players Matthew Goggin, Brendan Jones and James McLean also attended. He began drawing notice in Australia when he won the Western Australian Amateur and finished second in the Australian Amateur at the age of 17. Now he’s headed to a much bigger stage and feeling great about his future.

“I’m feeling pretty confident about my game now and I’m enjoying the moment,” he said.