I'm 17 and have chickenpox, how long will it last for someone my age as i know children tend to get it less harsh.

Nearly the same: The intensity has less to do with age than luck and other factors. Some people get a few spots, the average is about 200. You often run fever before you break & may break out for 5-7 days. Spots can be anywhere and in your mouth. You are contagious from moist cough/saliva and the material in the spots. You are considered contagious until the last spot is dry or 7 days, whichever is latest.