There is NO WAY TO TELL IF A WOMAN IS A VIRGIN OR NOT. Not unless you see her having sex, or if there is evidence of vaginal tearing.
Just like there is no way to tell if a man is a virgin or not. Not unless you see him having sex, or if there is evidence of anal tearing or friction rash on the penis (which can also be due to masturbation).
This whole virginity thing is a social concept. What does that mean? It means that at some point in time, society declared that virgins were the pinnacle of feminine restraint. In easier to understand terms, it means a bunch of men decided they were going to control women's sexuality.
In the far reaches of history, there was no such thing as misogeny (disrespect and hatred of women, inequality). You've all studied history, you heard the term hunter-gatherer. The true archaological facts are that the gatherers provided 80% of the food for the whole group and that there was an even amount of men and women doing both duties. There is ample evidence of this in fossil records, though most students are taught that men did all the physical work (which is not the case).
How does this relate to virginity? As society adopted the feudal system, things became inherintly inequal. Religion got mixed into things and suddenly women were not as good as men, were property and not people. The easiest way to establish that is to control a woman's body. Enter the virginity myth.
