I was always vague but honest. I may not have as much personal experience but I'm not ignorant or naive. So I'd simply state my opinion and say before hand that "I think" or "from what I hear" so it's never me acting like I'm speaking personally. I always speak in generality.

I still feel slightly odd once in a while when it's mentioned, but really it's just the "omg why don't you have a bf?!" that gets me because they go on about how a girl like my should have one and... What DOES one say to that?! I can give my input on a topic easily but the lack of having a boyfriend and/or virgin topic gets me. I just shrug now and say I don't know.