Here's the issue. Once I start talking for a while, I start asking serious questions. One of them is, "Are you a virgin/have you had any previous serious relationships?" Every. Single. Woman. I'm not exaggerating, every single woman I've talked to, has said yes, she's been in a previous relationship/had a bf. Over half have had oral sex. I talked to a few friends and they said I shouldn't ask questions like this because what's in the past is in the past and I should only be concerned about how they are right now.

Your friends are correct. Why is their past any of your concern if they moved on from it, especially for the sake of Allah (SWT)? You're better off asking a scholar, but as for now, I should remind you no one's perfect. If a person represented, then that's the end of that. You don't know if there dealing with unbelievable amounts of regret or not. To reject them despite them having improved is unreasonable. From what I've learned, what you do have the right to know is do they have any permanent issues like tattoos or STDs. That's something that CAN affect you. But, not the emotional stuff.

But see, I've never had a girlfriend, never had sex, never gotten a blowjob, and I don't think it's a lot to expect my wife to have been similar. Am I being naive?

You are naive. The Prophet (SAW) married Khadijah (RA) despite the fact she was married before and hence not a virgin. Yet she was his favorite wife. We're not better than those two, so I'm not sure we should be so worried about whether our wives are virgins or not. Anything good I said is Guidance from Allah (SWT) and anything bad I said is misguidance. W'Allahu 'alam