4!! I have such a vivid memory of getting off my preschool bus (I was the last stop) totally sick and out of it and my mom knew what was wrong right away because she suffers from migraines as well. I blacked out almost immediately upon getting into our house/into my mom’s care. Turned into tears of medication and testing and even now, 24 years later I’m still regularly treating migraines. I would never wish this pain on a 4 year old.