You're right, that's James McDonald. He's 18 years old...
He's only in his third season of riding and is still an apprentice. He was champion jockey last season, and will probably do it again this season. He's got 113 wins so far, 15 more than Mark Du Plessis.
He's the number one rider for Mark Walker, so he also rides Tell A Tale and lots of other nice stakes horses.