Not trying to jinx him- but he in Pres Cup already next month!
Tiger Woods knew he was ready to turn pro when he shot a 66 at age 20 in the second round of the 1996 British Open at Royal Lytham & St. Annes. He closed with a pair of 70s and tied for 22nd, his best finish as an amateur in 14 professional events. His father referred to it as his "coming out party."
Woods won the U.S. Amateur for the third straight time a month later, turned pro and was on his way.
For Jordan Spieth, his moment of realization came at the U.S. Open when he was 18.