The best way to describe what we are is Apprehensive.
When a guy hears that a girl hasn't had sex yet, his first question is obviously "well why?"
Now as you just explained, the opportunity hadn't presented itself.
But because you're a virgin, the first time a guy tries to have sex with you, knowing you're a virgin, your reaction will greatly affect how he judges your character, intentions, agenda, morals, character. A lot of things will then ride on your first sexual interaction.
Say you're seeing a guy and he tries to initiate sex. You don't think you've been seeing him long enough to feel comfortable doing anything with him yet. So you turn him down on it this time. Maybe after seeing him a little longer.
But knowing you're a virgin, he interprets your simple decision as a more solid choice that you're not ready to have sex yet. And he assumes you probably won't be for quite some time.
The way a guy looks at it is: "Hey, she's gone this long without having sex. She seems to be pretty consciously set on not doing it. Why would I be a pioneer and gamble time and effort on results that may or may not present themselves. Why would I be the one to convince her to have sex if no one else has?"
They kind of view your virginity like this:
If you were going to play the lottery, but had not heard a single case of someone winning, you'd be a little apprehensive.
Also, some guys feel that a girl becomes really clingy once he takes her virginity.
But if you're in this "situation" with a guy, are you talking about a sexual situation, or a relationship-esque situation?
I suppose how you treat the knowledge your virginity will affect the nature of your relationship.
If you tell him you're a virgin, he might try to take the relationship slower and be a little more sweet to you because he sees great potential in your ability to keep it that long. He could see it as a sign of faithfulness.
He could ALSO avoid going to far out of his way to commit to you until he's had sex with you.
Depends on what kind of guy he is.
All guys are different.