I think it's worth asking. Why waste your time or hers (not to mention emotions), if unvirginity is going to be a deal breaker?
I remember once I left it too late to ask (I just presumed, thinking it was like bible times) - it must've been the fourth or fifth date when I found out, and she was upset when I broke up afterward. Probably I was naive, but these days, there's no depths of depravity that people won't plumb and think it's totally normal (murdering kids is another one, but the virginity question addresses this too - a woman can't murder kids in her womb if her womb is unused/undefiled). As someone pointed out, these days, it's probably even worth checking she was born a girl. Confirmation of virginity is relatively minor in comparison to some of the necessary checks.
In my early 20's, there was a girl I met at a prayer meeting who was really pretty, and I felt connected to her, like I could feel her emotions, and stuff like that. Soon after I met her, I'd gotten something like a fuzzy word of knowledge about her, and she confessed some stuff that indicated she wasn't a virgin. So I never pursued anything with her, though I might have been interested if she was a virgin. She subtly indicated some interested in me once, right after having some boy troubles with another guy. I didn't follow up on the subtle cue. But she was pretty and sweet and all that. Another guy at church, a nice guy, dated her after that. She seemed like she always had to have a boyfriend.
Maybe a couple of years later, I was overseas, and I started dating this girl from another country, and I started to get the impression that I could do anything with her I wanted, which was a little concerning. Then she confessed she'd had sex with a previous boyfriend, and I realized I needed to break up with her. I suppose if I'd thought about it I would have realized since I was wanting to marry a virgin I should break up. But my convictions against senseless 'recreational dating' not aimed at marriage were not as strong then. But I think I was mainly concerned when I found out that she was not a virgin that the one thing keeping me from sleeping with her was me, and she wouldn't have been putting up resistance, so I broke it off. She got the impression that I was breaking it off because she wasn't a virgin and seemed to completely understand that without being wrongly indignant like a lot of anti 'slut shaming' girls nowadays would be in the west. I didn't correct her on that. We hadn't dated long, and ended amicably.
As far as finding out if someone is 'born again.' I wouldn't base it on whether they answered the question, 'Are you born again' correctly. I'd want to know what their faith is like, rather than the lingo they use. Someone can use 'born again' and not be born again, or not use the term and have genuine faith. They even use the term 'born again virgin' nowadays, and one doesn't have to be born again or a virgin to use that term.