This is an interesting question. I'm not too keen on the concept of virginity in the first place. It's definitely just a matter of opinion, since there are no physical markers of losing one's virginity (read about the hymen myth here: link
This is one of my favorite quotes from the article:
"Back to the virginity question, Roye states that she believes 'virginity is what the individual thinks it is. It certainly is for men, who bear no tell-tale signs of lost virginity.' She adds:
The concept of virginity has an emotional connotation. It is more than just the physical disruption of hymenal tissue.
If a young woman has had a sexual relationship with her partner, and she feels that she has lost her virginity, then she has, regardless of what actually happened to her hymen during the encounter. There are ancillary issues that each woman must answer for herself."
I think that stands for all people, and not just "young women".