When I use a word, it means what I want it to mean, no more, no less.
(from one of Lewis Carroll's works; I think it was a quote from the White Queen)
That's how I am with the words "virgin" and "virginity".
There was a time when "sex" meant penis in vagina, or rather that was the only sex anyone talked about openly. For a woman, having that for the first time involves a biological change, namely it breaks the hymen, hence it was seen as a highly significant event. Moreover it would have been possible to actually examine a woman to find out whether or not she was a virgin, and in some cultures husbands still place great importance on their new wife being a virgin. Lying about it would be pointless, since the deceit would be uncovered on the wedding night.
For many years (I am referring here to my teen and pre-teen years) I thought "virgin" was a term only applicable to women, and the first time someone referred to a boy being a virgin I thought it was some kind of joke. It wasn't of course; they were referring to the fact that he had not yet had (penetrative) sex with a girl. Then later on I learned there was such a thing as men fucking other men. Ever since then I've thought the term was unclear and a bit pointless. No doubt a man's first sexual experience with someone else, whatever the sex of the other person and whatever form the sex takes takes, is a highly significant event... but it's unlikely to be the first time he has ejaculated, so it's no big biological deal.
If someone has sucked you off but there has been no penetration, are you still a virgin? I don't think the answer matters much. More important is how significant the event was for you.