She had left Elmbridge Police Station when she was approached by a young man, who attacked her and left her with serious injuries.
Two 15-year-old boys and a 14-year-old boy were arrested in Claygate a short time later on suspicion of attempted murder.
Anyone who saw three young men in the areas of Esher and Claygate between 1.30 and 3.50pm yesterday afternoon is asked to contact police.