19f im still a virgin but i have a fishy odor down there and i dont know why?

The main cause of vaginal fishy genital odor is bacterial vaginosis, an overgrowth of mostly normal bacteria. BV usually occurs in sexually active women but is not rare in virgins, perhaps especially those who have had non-penetrating sexual experiences. (Some cases may follow oral sex, for example.) But the cause of BV is often unknown. See a doctor for evaluation and possible treatment.