What Is The Treatment For White Color Vaginal Discharge?

Hi I am only 16yrs old and I get white sticky stuff on my underwear, I don't know wht is it? My friend she is married, n had sex, she gets it when she don't have sex, but I never had sex, n I don't know why we get it? My friend used to get it as well, when she was 16, and until she got married? I just want to ask what is this, n is this a big issue, because i feel very bad... thank u