Can age spots start from the age of 11?

Dark spots= common. If by 'age spots' you mean freckles (dark flat spots) then early sun damage can cause them at 11 years old. Another 'age spot' is a raised darker lesion called a 'seborrheic keratosis' and are very common on sun exposed areas after 20-30 years old. Also it is said we make 10 new moles (congenital nevi) per year! the risk of melanoma goes up with early/prolonged sun exposure. Use sunscreen please.