What? Why are people saying 'Don't recieve oral?'.
If she gives you a BJ, and you cum, then she's probably feel really good about her BJ skills. Also - I find BJs are good warm up - I last much longer if the girl gives me a BJ before hand.
Just don't tell her! Male virginity doesn't mean shit! It's not the same thing as female virginity. Don't tell her now, and don't tell her after.
if she asks (how many people have you slept with), you could tell her then. But it's just not a big deal. By telling her, you'd just be providing reason to make things more complicated than they need to be.