Pubic hair is hair that grown on your genitals.
The time it starts to grow differs greatly. It can appear when you are only 8 years old, but also being 15 years old. With guys it normally appears after the scrotum and penis have increased in size and with girls it often appears after the start of breast growth.
At first the hair growth is sparse, with fine and soft hairs. After about a year the hairs become thicker and darker. When you are between 13 and 15 years the hairs normally spread and become coarser and curlier.
The colour of pubic hair is most often rather dark, but it can also be blond or red. Usually it’s a little darker than the hair on the head.
Girls can have just a small triangle. But it can also grow on the inner thighs, becoming an inverted triangle. Both are normal variations. Guys not only have hair above their penis, but often there is a line of hair running to the belly button. Many guys have (some) hair on their penis and scrotum. Both girls and guys may have hair growing on the perineum and in the anal cleft.
Axillary hair normally starts to grow 1 or 2 years after the appearance of pubic hair.

See also: shaving pubic hair