49 years old.
Because I have Ehlers Danlos Syndrome, people think I'm 40 yo - 43 yo. I often get "OMG?! No way you'll be 50 next year". Many Zebras (people with EDS) often report looking younger. I was still getting asked for ID until I was in my late 20s - early 30s, with the legal age to drink alcohol or by cigarettes (my ex smoked cigarettes) being 18 years old, in Australia. It's funny when I was older than the person who was asking to see my ID and they'd look embarrassed.