Inside a woman's vagina there is a thin membrane called a
hymen. This can easily be broken with a tampon or fingers but some women experience having their hymen torn when they first have sexual intercourse. This is where the term virgin has come from. A woman who has never had intercourse still had her hymen thus making her a virgin. It has nothing to do with experience. If you have never had sexual intercourse, then you are a virgin.
Masturbation plays no role in virginity. And as a man no it's not a big deal as long as you are open minded.