Giselle Mackinlay, a pupil at Micklefield School, Reigate, achieved the highest combined score at the National Triathlon Championship in Wolverhampton.
The event was organised by the British Modern Pentathlon Association. She came first in the Youth E Category and was also awarded the Best Shoot Medal with a score of 84 out of a potential score of 100.
The triathlon consisted of three events - running 1000m, swimming 50m and shooting ten shots with a pistol on a 10m range.
Giselle was invited to take part when she qualified in first place at the South East Region Triathlon in September.