I wouldnt be to worried but if you are as concerned as you sound make a appointment with an eye docter and have it checked out to make you feel better about it
Hello sorry to disappoint it is generally seen with aging even though you are 19. It is from cholesterol depositing at the end of Borman's membrane of the cornea. There's nothing really that can be done about it. You should however get a fasting cholesterol/Lipid level checked. Also you may want to start looking at the foods you are eating and try to cut back on fatty foods and those high in cholesterol like eggs and hamburgers etc. to help keep your cholesterol level in your body down.
Hope This Helps. Have A Nice Day.