Is it farther or further?
"age following childhood" (especially the period from the 15th to the 21st year), early 15c., from Middle French adolescence (14c.), from Latin adolescentia "youth," noun of state from adolescentem (see adolescent).
adolescence ad·o·les·cence (ād'l-ěs'əns)
The period of physical and psychological development from the onset of puberty to complete growth and maturity.