Is it rare for me get pad at 18?

PAD: If you're referring to peripheral arterial disease due to atherosclerosis(the commonest type) it would be extremely rare in your age group. Certain autoimmune vasculitis conditions cause obstruction of tiny blood vessels,however.

Very Unlikely: I assume you are referring to peripheral arterial disease (PAD). If so, it would be extremely rare in an 18yo unless you have some very rare congenital arterial disease.