Amanda, who started competing in Western performance events when she was just 8 years old, now trains for about four hours a day on weekdays - rising at 5.30 each morning and training before and after school - and up to eight hours a day at the weekends.
She said her love of horses and the satisfaction of success were her motivation.
''I'm a person who works hard and I like to see what you get when you work hard. For me to go to Australia [for the Trans Tasman Challenge] was an accomplishment for all the hard work I've put into it.
''And it's just the love of riding horses. It's just something I get up in the morning and do without second-thinking it.''
Amanda has one final selection camp, in January, to attend before she finds out whether she has made it into the national team for the youth world cup in the United States.