At what age do fainting episodes in vasovagal syncope usually start?

Around 10 years: Syncope is a common event in otherwise healthy children, especially in the second decade.

Ask cardio o neuro: Vasovagal syncopes are common but I investigate if they appear often. Some patients will require pacemakers or vasopressors to keep the blood pressure normal. Certain types of seizures must be ruled out, and an attempt to find the trigger is a must. I would say that usual things capable to trigger vasovagal syncope are not worrisome unless they appear too often. My guess: all ages.

Syncope: usually in teenage years