I recommend hiding the V card, usually women think you are lying about it anyway, especially once they reveal that they are a virgin to you, then it's easy to say that you are also a virgin back and try and obviously sack her. It's more credibile if you tell her after the fact, or if she just simply reads that about you.
In my experience, revealing you are a virgin to someone is not especially helpful, but knowing how to 'excite' her and want to have sex with you rather than the next guy would go allot further. I'd usually let her just read into it, or portray it in a context that I'm trying to hide it and I'm ashamed of revealing it so it would come across as credible.